A166554 -id:A166554 - cp's OEIS frontend

A224869 a(n) = n*( a(n-1)+1 ), initialized by a(1) = -1.

-1, 0, 3, 16, 85, 516, 3619, 28960, 260649, 2606500, 28671511, 344058144, 4472755885, 62618582404, 939278736075, 15028459777216, 255483816212689, 4598708691828420, 87375465144739999, 1747509302894800000, 36697695360790800021, 807349297937397600484

Offset: 1

Alex Ratushnyak, Jul 22 2013

			a(4) = 4*(a(3)+1) = 4*4 = 16.

Cf. A007526, A038156, A166554, A121662 (3rd column).

A224869[1] := -1; A224869[n_] := A224869[n - 1]n + n; Table[A224869[n], {n, 40}] (* Alonso del Arte, Jul 22 2013 *)

a=-1
for n in range(2,24):
  print(a, end=', ')
  a= n*(a+1)

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

A166680 a(n) = n*(a(n-1)-4), a(0) = 1.

Original entry on oeis.org

1, -3, -14, -54, -232, -1180, -7104, -49756, -398080, -3582756, -35827600, -394103644, -4729243776, -61480169140, -860722368016, -12910835520300, -206573368324864, -3511747261522756, -63211450707409680

Offset: 0

Philippe Deléham, Oct 18 2009

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Cf. A000142, A166554, A165793, A165814.

RecurrenceTable[{a[0]==1,a[n]==n(a[n-1]-4)},a,{n,20}] (* Harvey P. Dale, Apr 18 2014 *)
FoldList[#1*#2 - 4 #2 &, 1, Range[50]] (* G. C. Greubel, May 23 2016 *)

a(n) = n! - 4*floor(e*n!) + 4, n>0. - Gary Detlefs, Jun 19 2010

cp's OEIS Frontend

A224869 a(n) = n*( a(n-1)+1 ), initialized by a(1) = -1.

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