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%I #8 Jun 13 2015 00:52:22
%S 1,1,8,24,59,115,202,322,485,693,956,1276,1663,2119,2654,3270,3977,
%T 4777,5680,6688,7811,9051,10418,11914,13549,15325,17252,19332,21575,
%U 23983,26566,29326,32273,35409,38744,42280,46027,49987,54170,58578,63221
%N A129957(n) - n*(n-1)/2.
%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (3,-2,-2,3,-1).
%F a(n) = (1+(-1)^n+n-n^2+2*n^3)/2. G.f.: (1-2*x+7*x^2+4*x^3+2*x^4)/((1-x)^4*(1+x)). [_Colin Barker_, Sep 10 2012]
%t f[n_]:= If[Mod[n, 2] == 0, n^3 + 1, n^3]; Table[f[n] - n*(n - 1)/2, {n, 0, 40}]
%Y Cf. A129957, A129958.
%K nonn,easy
%O 0,3
%A _Roger L. Bagula_, Jun 10 2007
%E Edited, corrected and extended by _Stefan Steinerberger_, Jul 21 2007
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