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 A344496 a(0)=0; for n > 0, a(n) = a(n-1)*n + n if n is odd, (a(n-1) + n)*n otherwise. 0
 0, 1, 6, 21, 100, 505, 3066, 21469, 171816, 1546353, 15463630, 170099941, 2041199436, 26535592681, 371498297730, 5572474465965, 89159591455696, 1515713054746849, 27282834985443606, 518373864723428533, 10367477294468571060, 217717023183839992281, 4789774510044479830666 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS FORMULA a(n) ~ n! * (3*exp(1)/2 + exp(-1)/2). - Vaclav Kotesovec, Jun 05 2021 EXAMPLE a(0) = 0; a(1) = a(0)*1 + 1 = 0 + 1 = 1; a(2) = (a(1)+2)* 2 = (1 + 2)*2 = 6; a(3) = a(2)*3 + 3 = 6*3 + 3 = 21; a(4) = (a(3)+4)* 4 = (21 + 4)*4 = 100. MAPLE a:= proc(n) a(n):= n*a(n-1) + n^(2-(n mod 2)) end: a(0):= 0: seq(a(n), n=0..22); # Alois P. Heinz, May 21 2021 MATHEMATICA a[0] = 0; a[n_] := a[n] = n * (a[n - 1] + If[OddQ[n], 1, n]); Array[a, 30, 0] (* Amiram Eldar, May 21 2021 *) Table[n*(-1 + 3*E*Gamma[n, 1] + (n-1)*Subfactorial[n-2])/2, {n, 0, 30}] (* Vaclav Kotesovec, Jun 05 2021 *) CROSSREFS Cf. A344262, A344495. Sequence in context: A009247 A093774 A151612 * A012773 A012662 A012418 Adjacent sequences: A344493 A344494 A344495 * A344497 A344498 A344499 KEYWORD nonn AUTHOR Amrit Awasthi, May 21 2021 STATUS approved

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Last modified March 28 07:32 EDT 2023. Contains 361577 sequences. (Running on oeis4.)