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A131874

a(n) = (7*n^2 + 15*n + 2) / 2.

1, 12, 30, 55, 87, 126, 172, 225, 285, 352, 426, 507, 595, 690, 792, 901, 1017, 1140, 1270, 1407, 1551, 1702, 1860, 2025, 2197, 2376, 2562, 2755, 2955, 3162, 3376, 3597, 3825, 4060, 4302, 4551, 4807, 5070, 5340, 5617, 5901, 6192, 6490, 6795, 7107, 7426

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OFFSET

0,2

COMMENTS

Row sums of triangle A131873.

LINKS

Table of n, a(n) for n=0..45.

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

FORMULA

Binomial transform of (1, 11, 7, 0, 0, 0, ...).

a(n) = a(n-1) + 7*n + 4, (with a(0)=1). - Vincenzo Librandi, Nov 23 2010

a(n) = (2 + 15*n + 7*n^2)/2;