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 A122017 a(n) = if n even then a(n - 1) - (n - 1)*a(n - 2) otherwise 2*(a(n - 1) + (n - 1)*a(n - 2])). 0
 1, 2, 1, 10, 7, 94, 59, 1246, 833, 21602, 14105, 460250, 305095, 11656190, 7689955, 341753230, 226403905, 11388911170, 7540044785, 425080891690, 281820040775, 17566875749150, 11648654892875, 796239842748350, 528320780212225 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS MATHEMATICA a[0] = 1; a[1] = 2; a[n_] := a[n] = If[Mod[n, 2] == 0, a[n - 1] - (n - 1)*a[n - 2], 2*(a[n - 1] + (n - 1)*a[n - 2])] b = Table[a[n], {n, 0, 30}] CROSSREFS Cf. A000898, A121966. Sequence in context: A225470 A081099 A213252 * A219900 A136233 A113088 Adjacent sequences:  A122014 A122015 A122016 * A122018 A122019 A122020 KEYWORD nonn AUTHOR Roger L. Bagula, Sep 11 2006 EXTENSIONS Edited by N. J. A. Sloane, Sep 13 2006 STATUS approved

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Last modified May 24 06:53 EDT 2019. Contains 323529 sequences. (Running on oeis4.)