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---
id: 5900f40d1000cf542c50ff20
title: 'Problem 161: Triominoes'
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challengeType: 5
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forumTopicId: 301795
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dashedName: problem-161-triominoes
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---
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# --description--
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A triomino is a shape consisting of three squares joined via the edges.
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There are two basic forms:
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If all possible orientations are taken into account there are six:
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Any n by m grid for which nxm is divisible by 3 can be tiled with triominoes. If we consider tilings that can be obtained by reflection or rotation from another tiling as different there are 41 ways a 2 by 9 grid can be tiled with triominoes:
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In how many ways can a 9 by 12 grid be tiled in this way by triominoes?
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# --hints--
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`euler161()` should return 20574308184277972.
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```js
assert.strictEqual(euler161(), 20574308184277972);
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```
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# --seed--
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## --seed-contents--
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```js
function euler161() {
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return true;
}
euler161();
```
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# --solutions--
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```js
// solution required
```
