are the Fibonacci numbers,
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, ...
Taken modulo 7, we get the sequence
0, 1, 1, 2, 3, 5, 1, 6, 0, 6, 6, 5, 4, 2, 6, 1, ...
that repeats with period 16 (this is known as the 7th Pisano period).
This is to say,
so that
