Question 152
Jacopo has $6$ colours available (white among them) to colour all the integers. However, he wants to respect these conditions: $n$ and $n+5$ must have the same colour for every integer $n$, and moreover, if $ab$ is white, then at least one of $a$ and $b$ must be white. In how many ways can Jacopo colour the integers?
(A) 156
(B) 656
(C) 3181
(D) 3906
(E) 3936
(A) 156
(B) 656
(C) 3181
(D) 3906
(E) 3936