The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A166677 a(n)= n*(a(n-1)+4), a(0)=1. 1
 1, 5, 18, 66, 280, 1420, 8544, 59836, 478720, 4308516, 43085200, 473937244, 5687246976, 73934210740, 1035078950416, 15526184256300, 248418948100864, 4223122117714756, 76016198118865680, 1444307764258447996 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS G. C. Greubel, Table of n, a(n) for n = 0..200 FORMULA a(n) = n!+4*floor(e*n!)-4, n>0. [Gary Detlefs, Jun 06 2010] From Robert Israel, May 22 2016: (Start) a(n) = n!*(1 + Sum_{k=0..n-1} 4/k!) = n! + 4 e n Gamma(n,1). E.g.f.: (1+4*x*exp(x))/(1-x). (End) MAPLE f:= gfun:-rectoproc({a(n)=n*(a(n-1)+4), a(0)=1}, a(n), remember): map(f, [\$0..30]); # Robert Israel, May 22 2016 MATHEMATICA FoldList[#1*#2 + 4 #2 &, 1, Range[19]] (* Robert G. Wilson v, Jul 07 2012 *) CROSSREFS Cf. A000142, A033540, A165792, A165813 Sequence in context: A153373 A225015 A371871 * A318062 A158879 A322497 Adjacent sequences: A166674 A166675 A166676 * A166678 A166679 A166680 KEYWORD easy,nonn AUTHOR Philippe Deléham, Oct 18 2009 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified April 18 08:27 EDT 2024. Contains 371769 sequences. (Running on oeis4.)