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 A129959 A129957(n) - n*(n-1)/2. 1
 1, 1, 8, 24, 59, 115, 202, 322, 485, 693, 956, 1276, 1663, 2119, 2654, 3270, 3977, 4777, 5680, 6688, 7811, 9051, 10418, 11914, 13549, 15325, 17252, 19332, 21575, 23983, 26566, 29326, 32273, 35409, 38744, 42280, 46027, 49987, 54170, 58578, 63221 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Index entries for linear recurrences with constant coefficients, signature (3,-2,-2,3,-1). FORMULA 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] MATHEMATICA f[n_]:= If[Mod[n, 2] == 0, n^3 + 1, n^3]; Table[f[n] - n*(n - 1)/2, {n, 0, 40}] CROSSREFS Cf. A129957, A129958. Sequence in context: A302489 A099041 A306056 * A256533 A177719 A317234 Adjacent sequences:  A129956 A129957 A129958 * A129960 A129961 A129962 KEYWORD nonn,easy AUTHOR Roger L. Bagula, Jun 10 2007 EXTENSIONS Edited, corrected and extended by Stefan Steinerberger, Jul 21 2007 STATUS approved

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Last modified February 24 17:29 EST 2020. Contains 332209 sequences. (Running on oeis4.)