A165793 a(0)=1, a(n)=n*(a(n-1)-2).

1, -1, -6, -24, -104, -530, -3192, -22358, -178880, -1609938, -16099400, -177093422, -2125121088, -27626574170, -386772038408, -5801580576150, -92825289218432, -1578029916713378, -28404538500840840

Offset

0,3

Links

G. C. Greubel, Table of n, a(n) for n = 0..250

Formula

a(n) = n! - 2*floor(e*n!)+2 , n>0. - Gary Detlefs, Jun 19 2010

Mathematica

RecurrenceTable[{a[0]==1, a[n]==n*(a[n-1]-2)}, a[n], {n, 30}] (* Harvey P. Dale, Jul 19 2011 *)
FoldList[#1*#2 - 2 #2 &, 1, Range[25]] (* G. C. Greubel, Apr 08 2016 *)

Crossrefs

Sequence in context: A120583 A089378 A074414 * A344274 A122740 A034432

Adjacent sequences: A165790 A165791 A165792 * A165794 A165795 A165796

Keyword

sign

Author

Philippe Deléham, Sep 26 2009

Extensions

Corrected by Harvey P. Dale, Jul 19 2011

Status

approved