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---
id: 5900f4b21000cf542c50ffc5
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title: 'Problema 326: Somas de módulos'
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challengeType: 5
forumTopicId: 301983
dashedName: problem-326-modulo-summations
---
# --description--
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Considere an como sendo uma sequência recursivamente definida por: $a_1 = 1$, $\displaystyle a_n = \left(\sum_{k = 1}^{n - 1} k \times a_k\right)\bmod n$.
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Portanto, os primeiros 10 elementos de $a_n$ são: 1, 1, 0, 3, 0, 3, 5, 4, 1, 9.
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Considere $f(N, M)$ como representando o número de pares $(p, q)$, de modo que:
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$$ 1 \le p \le q \le N \\; \text{e} \\; \left(\sum_{i = p}^q a_i\right)\bmod M = 0$$
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Pode-se ver que $f(10, 10) = 4$ com os pares (3,3), (5,5), (7,9) e (9,10).
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Você também é informado de que $f({10}^4, {10}^3) = 97.158$.
Encontre $f({10}^{12}, {10}^6)$.
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# --hints--
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`moduloSummations()` deve retornar `1966666166408794400` .
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```js
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assert.strictEqual(moduloSummations(), 1966666166408794400);
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```
# --seed--
## --seed-contents--
```js
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function moduloSummations() {
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return true;
}
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moduloSummations();
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```
# --solutions--
```js
// solution required
```