--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 $T({10}^{12})$ modulo ${10}^8$?

--hints--

toursOnPlayingBoard() should return 15836928.

assert.strictEqual(toursOnPlayingBoard(), 15836928);

--seed--

--seed-contents--

function toursOnPlayingBoard() {

  return true;
}

toursOnPlayingBoard();

--solutions--

// solution required