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A155120
a(n) = 2*(n^3 + n^2 + n - 1).
3
-2, 4, 26, 76, 166, 308, 514, 796, 1166, 1636, 2218, 2924, 3766, 4756, 5906, 7228, 8734, 10436, 12346, 14476, 16838, 19444, 22306, 25436, 28846, 32548, 36554, 40876, 45526, 50516, 55858
OFFSET
0,1
FORMULA
a(n) = 2*(n^3 +n^2 +n -1).
G.f.: 2*(-1 +6*x -x^2 +2*x^3)/(1-x)^4.
E.g.f.: 2*(-1 + 3*x + 4*x^2 + x^3)*exp(x). - G. C. Greubel, Mar 25 2021
MAPLE
seq( 2*(n^3 +n^2 +n -1), n=0..40); # G. C. Greubel, Mar 25 2021
MATHEMATICA
Table[-2 +2n +2n^2 +2n^3, {n, 0, 30}]
LinearRecurrence[{4, -6, 4, -1}, {-2, 4, 26, 76}, 40] (* Harvey P. Dale, Jun 06 2014 *)
PROG
(Magma) [2*(n^3+n^2+n-1): n in [0..40] ]; // Vincenzo Librandi, May 23 2011
(Sage) [2*(n^3 +n^2 +n -1) for n in (0..40)] # G. C. Greubel, Mar 25 2021
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Roger L. Bagula, Jan 20 2009
STATUS
approved