P402
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Integer-valued Polynomials

ℹ️Published on Saturday, 17th November 2012, 07:00 pm; Solved by 467;
Difficulty rating: 55%

It can be shown that the polynomial $n^4 + 4n^3 + 2n^2 + 5n$ is a multiple of $6$ for every integer $n$. It can also be shown that $6$ is the largest integer satisfying this property.

Define $M(a, b, c)$ as the maximum $m$ such that $n^4 + an^3 + bn^2 + cn$ is a multiple of $m$ for all integers $n$. For example, $M(4, 2, 5) = 6$.

Also, define $S(N)$ as the sum of $M(a, b, c)$ for all $0 \lt a, b, c \leq N$.

We can verify that $S(10) = 1972$ and $S(10000) = 2024258331114$.

Let $F_k$ be the Fibonacci sequence:
$F_0 = 0$, $F_1 = 1$ and
$F_k = F_{k-1} + F_{k-2}$ for $k \geq 2$.

Find the last $9$ digits of $\sum S(F_k)$ for $2 \leq k \leq 1234567890123$.



Soluzione

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