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 A224869 a(n) = n*( a(n-1)+1 ), initialized by a(1) = -1. 2
 -1, 0, 3, 16, 85, 516, 3619, 28960, 260649, 2606500, 28671511, 344058144, 4472755885, 62618582404, 939278736075, 15028459777216, 255483816212689, 4598708691828420, 87375465144739999, 1747509302894800000, 36697695360790800021, 807349297937397600484 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Table of n, a(n) for n=1..22. FORMULA a(n) +(-n-2)*a(n-1) +(2*n-1)*a(n-2) +(-n+2)*a(n-3)=0. - R. J. Mathar, Jul 28 2013 a(n) = exp(1)*n*Gamma(n,1) - 2*Gamma(n+1,0). - Martin Clever Mar 27 2023 EXAMPLE a(4) = 4*(a(3)+1) = 4*4 = 16. MATHEMATICA A224869[1] := -1; A224869[n_] := A224869[n - 1]n + n; Table[A224869[n], {n, 40}] (* Alonso del Arte, Jul 22 2013 *) PROG (Python) a=-1 for n in range(2, 24): print str(a)+', ', a= n*(a+1) CROSSREFS Cf. A007526, A038156, A166554, A121662 (3rd column). Sequence in context: A056369 A056360 A278681 * A163604 A151329 A356402 Adjacent sequences: A224866 A224867 A224868 * A224870 A224871 A224872 KEYWORD sign,easy AUTHOR Alex Ratushnyak, Jul 22 2013 STATUS approved

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Last modified August 13 21:35 EDT 2024. Contains 375144 sequences. (Running on oeis4.)