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A058372
a(n) = -(n + 1)*(2*n^2 + n - 12)/6.
2
2, 3, 1, -6, -20, -43, -77, -124, -186, -265, -363, -482, -624, -791, -985, -1208, -1462, -1749, -2071, -2430, -2828, -3267, -3749, -4276, -4850, -5473, -6147, -6874, -7656, -8495, -9393, -10352, -11374, -12461, -13615, -14838, -16132, -17499, -18941, -20460, -22058, -23737
OFFSET
0,1
FORMULA
G.f.: (2 - 5*x + x^2)/(1 - x)^4.
MATHEMATICA
LinearRecurrence[{4, -6, 4, -1}, {2, 3, 1, -6}, 100] (* Paolo Xausa, Oct 22 2023 *)
PROG
(Magma) [-(n + 1)*(2*n^2 + n - 12)/6 : n in [0..80]]; // Wesley Ivan Hurt, Aug 19 2022
CROSSREFS
Sequence in context: A075263 A130850 A130405 * A128264 A375258 A232435
KEYWORD
sign,easy
AUTHOR
N. J. A. Sloane, Dec 18 2000
STATUS
approved