{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-04-16T00:12:35.000Z","description":"Problems submitted by members of the MATLAB Central community.","is_default":true,"created_by":161519,"badge_id":null,"featured":false,"trending":false,"solution_count_in_trending_period":0,"trending_last_calculated":"2026-04-16T00:00:00.000Z","image_id":null,"published":true,"community_created":false,"status_id":2,"is_default_group_for_player":false,"deleted_by":null,"deleted_at":null,"restored_by":null,"restored_at":null,"description_opc":null,"description_html":null,"published_at":null},"problems":[{"id":59492,"title":"Quasi-Carmichael Numbers","description":"Determine if the provided inputs are Quasi-Carmichael numbers and output a logical matrix of the same size as the input.","description_html":"\u003cdiv style = \"text-align: start; line-height: 20.44px; min-height: 0px; white-space: normal; color: rgb(0, 0, 0); font-family: Menlo, Monaco, Consolas, monospace; font-style: normal; font-size: 14px; font-weight: 400; text-decoration: none solid rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 20.9896px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 406.493px 10.4861px; transform-origin: 406.493px 10.4948px; vertical-align: baseline; \"\u003e\u003cdiv style=\"font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 383.49px 10.4861px; text-align: left; transform-origin: 383.498px 10.4948px; white-space-collapse: preserve; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003eDetermine if the provided inputs are Quasi-Carmichael numbers and output a logical matrix of the same size as the input.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function yn = isQuasiCarmichael(m)\r\n  yn=false(size(m));\r\nend","test_suite":"%%\r\nd=webread('https://oeis.org/A257750/b257750.txt');\r\nfilename = 'd.txt';\r\nfid = fopen(filename,'w');\r\nfprintf(fid,'%s',d);\r\nfclose(fid);\r\nm=readmatrix('d.txt');\r\nm=m(:,2)';\r\nr=randi(3e8,size(m));\r\nM=[m,r];\r\nrng(3141);\r\nyn = isQuasiCarmichael(M(randperm(length(M),100)));\r\nyn_correct=logical([1   0   1   0   0   1   1   0   0   1   1   0   0   0   0   1   1   1   1   0   0   0   0   1   0   1   0   1   1   1   1   1   0   0   0   1   0   0   0   1   1   1   0   0   0   1   1   1   1   0   0   1   1   1   0   1   1   0   0   0   1   1   0   0   0   0   1   1   1   0   1   0   1   0   0   0   1   1   1   0   0   0   0   0   0   0   0   0   1   0   0   1   1   0   0   0   0   1   1   0]);\r\nassert(isequal(yn,yn_correct));\r\n%%\r\nm=readmatrix('d.txt');\r\nm=m(:,2)';\r\nr=randi(3e8,size(m));\r\nM=[m,r];\r\nrng(2718);\r\ny=reshape(M(randperm(length(M),49)),7,7);\r\nyn=isQuasiCarmichael(y);\r\nyn_correct=logical([1   1   0   0   1   1   1\r\n   0   0   0   1   1   0   0\r\n   0   0   0   0   0   1   1\r\n   1   0   0   1   0   1   0\r\n   1   0   0   1   1   0   1\r\n   1   1   1   0   0   0   0\r\n   0   1   1   1   1   1   1]);\r\nassert(isequal(yn,yn_correct));\r\n%%\r\nm=readmatrix('d.txt');\r\nm=m(:,2)';\r\nr=randi(3e8,size(m));\r\nM=[m,r];\r\nrng(2236);\r\ny=reshape(M(randperm(length(M),27)),3,3,3);\r\nyn=isQuasiCarmichael(y);\r\nyn_correct(:,:,1) =logical([0   0   0\r\n                    0   1   1\r\n                    1   0   0]);\r\nyn_correct(:,:,2) =logical([0   0  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'web');\r\nassert(~not_allowed)\r\n","published":true,"deleted":false,"likes_count":1,"comments_count":0,"created_by":145982,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":2,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2023-12-14T21:47:22.000Z","updated_at":"2023-12-14T21:47:22.000Z","published_at":"2023-12-14T21:47:22.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eDetermine if 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block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 406.493px 10.4861px; transform-origin: 406.493px 10.4948px; vertical-align: baseline; \"\u003e\u003cdiv style=\"font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 383.49px 10.4861px; text-align: left; transform-origin: 383.498px 10.4948px; white-space-collapse: preserve; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003eDetermine if the provided inputs are Quasi-Carmichael numbers and output a logical matrix of the same size as the input.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function yn = isQuasiCarmichael(m)\r\n  yn=false(size(m));\r\nend","test_suite":"%%\r\nd=webread('https://oeis.org/A257750/b257750.txt');\r\nfilename = 'd.txt';\r\nfid = fopen(filename,'w');\r\nfprintf(fid,'%s',d);\r\nfclose(fid);\r\nm=readmatrix('d.txt');\r\nm=m(:,2)';\r\nr=randi(3e8,size(m));\r\nM=[m,r];\r\nrng(3141);\r\nyn = isQuasiCarmichael(M(randperm(length(M),100)));\r\nyn_correct=logical([1   0   1   0   0   1   1   0   0   1   1   0   0   0   0   1   1   1   1   0   0   0   0   1   0   1   0   1   1   1   1   1   0   0   0   1   0   0   0   1   1   1   0   0   0   1   1   1   1   0   0   1   1   1   0   1   1   0   0   0   1   1   0   0   0   0   1   1   1   0   1   0   1   0   0   0   1   1   1   0   0   0   0   0   0   0   0   0   1   0   0   1   1   0   0   0   0   1   1   0]);\r\nassert(isequal(yn,yn_correct));\r\n%%\r\nm=readmatrix('d.txt');\r\nm=m(:,2)';\r\nr=randi(3e8,size(m));\r\nM=[m,r];\r\nrng(2718);\r\ny=reshape(M(randperm(length(M),49)),7,7);\r\nyn=isQuasiCarmichael(y);\r\nyn_correct=logical([1   1   0   0   1   1   1\r\n   0   0   0   1   1   0   0\r\n   0   0   0   0   0   1   1\r\n   1   0   0   1   0   1   0\r\n   1   0   0   1   1   0   1\r\n   1   1   1   0   0   0   0\r\n   0   1   1   1   1   1   1]);\r\nassert(isequal(yn,yn_correct));\r\n%%\r\nm=readmatrix('d.txt');\r\nm=m(:,2)';\r\nr=randi(3e8,size(m));\r\nM=[m,r];\r\nrng(2236);\r\ny=reshape(M(randperm(length(M),27)),3,3,3);\r\nyn=isQuasiCarmichael(y);\r\nyn_correct(:,:,1) =logical([0   0   0\r\n                    0   1   1\r\n                    1   0   0]);\r\nyn_correct(:,:,2) =logical([0   0   1\r\n                    0   0   1\r\n                    0   0   0]);\r\nyn_correct(:,:,3) =logical([0   0   0\r\n                    1   0   0\r\n                    0   0   1]);\r\nassert(isequal(yn,yn_correct));\r\n%%\r\nm=readmatrix('d.txt');\r\nm=m(:,2)';\r\nr=randi(3e8,size(m));\r\nrng(3137);\r\ny1=isQuasiCarmichael(m(randi(length(m),1,10)));\r\ny2=isQuasiCarmichael(r(randi(length(r),1,10)));\r\nassert(isequal(nnz(y1),10));\r\nassert(isequal(nnz(y2),0));\r\n%%\r\nassert(isequal(isQuasiCarmichael([1 1e15]),logical([0 0])));\r\nfiletext = fileread('isQuasiCarmichael.m');\r\nnot_allowed = contains(filetext, 'https') || contains(filetext, 'global') || contains(filetext, 'persistent') || contains(filetext, 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