This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A088336 Number of permutations in the symmetric group S_n that have even number of transpositions in their cycle decomposition. 5
 1, 1, 1, 3, 18, 90, 480, 3360, 27720, 249480, 2479680, 27276480, 327650400, 4259455200, 59623724160, 894355862400, 14309953257600, 243269205379200, 4378836875212800, 83197900629043200, 1663958347802150400, 34943125303845158400, 768748742605299456000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..200 FORMULA E.g.f.: (exp(-x^2)+1)/(1-x)/2. - Vladeta Jovovic, Nov 09 2003 a(n) ~ n! * (1+exp(-1))/2. - Vaclav Kotesovec, Oct 08 2013 MATHEMATICA mx = 21; Rest[ Range[0, mx]! CoefficientList[ Series[(Exp[-x^2] + 1)/(1 - x)/2, {x, 0, mx}], x]] (* Robert G. Wilson v, May 04 2013 *) PROG (PARI) x='x+O('x^50); Vec(serlaplace((exp(-x^2)+1)/(1-x)/2)) \\ G. C. Greubel, Aug 20 2017 CROSSREFS Cf. A062282. Sequence in context: A006568 A181955 A147518 * A133594 A272492 A092691 Adjacent sequences:  A088333 A088334 A088335 * A088337 A088338 A088339 KEYWORD nonn AUTHOR Yuval Dekel (dekelyuval(AT)hotmail.com), Nov 07 2003 EXTENSIONS More terms from Robert G. Wilson v, May 04 2013 a(0) = 1 prepended by Alois P. Heinz, Jun 14 2015 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
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified March 21 07:23 EDT 2019. Contains 321367 sequences. (Running on oeis4.)