id	title	challengeType	forumTopicId	dashedName
5900f4591000cf542c50ff6c	Problem 237: Tours on a 4 x n playing board	5	301882	problem-237-tours-on-a-4-x-n-playing-board

--description--

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?

--hints--

euler237() should return 15836928.

assert.strictEqual(euler237(), 15836928);

function euler237() {

  return true;
}

euler237();

// solution required