a is multiple of 7

Hello. I have a problem that says "show that number a=13+2^2013 is a multiple of 7". i have to implement the solution, which is a=13+(2^3)^671=13+8^671=13+(7+1)^671=13+Multiple7+1=Multiple7. How can I do that? thank you.

Answer 1

[Steven Lord]

Use modular exponentiation.