This site is supported by donations to The OEIS Foundation.

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A056543 a(n) = n*a(n-1) - 1 with a(1)=1. 2
 1, 1, 2, 7, 34, 203, 1420, 11359, 102230, 1022299, 11245288, 134943455, 1754264914, 24559708795, 368395631924, 5894330110783, 100203611883310, 1803665013899579, 34269635264092000, 685392705281839999 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS If s(n) is a sequence defined by s(0)=x, s(n)=(n+1)*s(n-1)+k, n>0, then s(n) = n!*x +(n! - a(n+1))*k. - Gary Detlefs, Jun 10 2010 LINKS FORMULA a(n) = ceiling((3-e)*n!) = n! - A056542(n) = 2*n! - A002627(n) = 3*n! - A000522(n). a(n) = n!*(2-Sum_{k=1..n}{k!^(-1)}), with n>=1. - Paolo P. Lava, Jun 25 2010 EXAMPLE a(4) = 4*a(3) - 1 = 4*2 - 1 = 7. MATHEMATICA lst={1}; s=-1; Do[s+=s++n; AppendTo[lst, Abs[s]], {n, 5!}]; lst (* Vladimir Joseph Stephan Orlovsky, Oct 23 2008 *) CROSSREFS Sequence in context: A117399 A145345 A212027 * A075834 A011800 A112916 Adjacent sequences:  A056540 A056541 A056542 * A056544 A056545 A056546 KEYWORD easy,nonn AUTHOR Henry Bottomley, Jun 20 2000 EXTENSIONS More terms from James A. Sellers, Jul 04 2000 STATUS approved

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

Last modified December 8 11:23 EST 2016. Contains 278939 sequences.