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A155121
a(n) = 2*n*(1 + n + n^2 + n^3) - 3.
2
-3, 5, 57, 237, 677, 1557, 3105, 5597, 9357, 14757, 22217, 32205, 45237, 61877, 82737, 108477, 139805, 177477, 222297, 275117, 336837, 408405, 490817, 585117, 692397, 813797, 950505, 1103757, 1274837, 1465077, 1675857
OFFSET
0,1
FORMULA
a(n) = 2*n*(1 + n + n^2 + n^3) - 3.
G.f.: (3 - 20*x - 2*x^2 - 32*x^3 + 3*x^4)/(x-1)^5.
From Bruno Berselli, Dec 16 2010: (Start)
a(n) = 4*A071237(n) - 3.
a(n) = 2*A024003(n)/(1-n) - 5 (n>1). (End)
E.g.f.: (-3 + 8*x + 22*x^2 + 14*x^3 + 2*x^4)*exp(x). - G. C. Greubel, Mar 25 2021
MAPLE
seq( -3 +2*n +2*n^2 +2*n^3 +2*n^4, n=0..40); # G. C. Greubel, Mar 25 2021
MATHEMATICA
Table[-3 +2n +2n^2 +2n^3 +2n^4, {n, 0, 30}]
PROG
(Magma) [2*n*(1+n+n^2+n^3)-3: n in [0..40] ]; // Vincenzo Librandi, May 23 2011
(Sage) [-3 +2*n +2*n^2 +2*n^3 +2*n^4 for n in (0..40)] # G. C. Greubel, Mar 25 2021
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Roger L. Bagula, Jan 20 2009
STATUS
approved