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 A355988 a(n) = n! / floor(n/3)!. 4
 1, 1, 2, 6, 24, 120, 360, 2520, 20160, 60480, 604800, 6652800, 19958400, 259459200, 3632428800, 10897286400, 174356582400, 2964061900800, 8892185702400, 168951528345600, 3379030566912000, 10137091700736000, 223016017416192000, 5129368400572416000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Table of n, a(n) for n=0..23. FORMULA E.g.f.: (1 - x^3) * exp(x^3)/(1 - x). MATHEMATICA a[n_] := n!/Floor[n/3]!; Array[a, 24, 0] (* Amiram Eldar, Jul 22 2022 *) PROG (PARI) a(n) = n!/(n\3)!; (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace((1-x^3)*exp(x^3)/(1-x))) CROSSREFS Cf. A081125, A355990. Sequence in context: A364425 A178010 A366368 * A330043 A062348 A189856 Adjacent sequences: A355985 A355986 A355987 * A355989 A355990 A355991 KEYWORD nonn,easy AUTHOR Seiichi Manyama, Jul 22 2022 STATUS approved

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Last modified September 13 17:14 EDT 2024. Contains 375910 sequences. (Running on oeis4.)