Problem 237: Tours on a 4 x n playing board
Let T(n) be the number of tours over a 4 × n playing board such that:
The tour starts in the top left corner.
The tour consists of moves that are up, down, left, or right one square.
The tour visits each square exactly once.
The tour ends in the bottom left corner.
The diagram shows one tour over a 4 × 10 board:
T(10) is 2329. What is T(1012) modulo 108?
Test
{{test}}Console output