The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A003221 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A003221

Number of even permutations of length n with no fixed points.
(history; published version)

#56 by Alois P. Heinz at Tue Feb 11 19:52:24 EST 2020

STATUS

proposed

approved

#55 by Michael De Vlieger at Tue Feb 11 18:01:03 EST 2020

STATUS

editing

proposed

#54 by Michael De Vlieger at Tue Feb 11 18:01:00 EST 2020

LINKS

Karen Meagher, Peter Sin, <a href="https://arxiv.org/abs/1911.11252">All 2-transitive groups have the EKR-module property</a>, arXiv:1911.11252 [math.CO], 2019.

STATUS

approved

editing

#53 by Peter Luschny at Tue May 09 13:51:13 EDT 2017

STATUS

editing

approved

#52 by Peter Luschny at Tue May 09 13:51:05 EDT 2017

MAPLE

A003221 := n -> ((-1)^n*hypergeom([-n, 1], [], 1)-(-1)^n*(n-1))/2:

seq(simplify(A003221(n)), n=0..22); # Peter Luschny, May 09 2017

STATUS

approved

editing

#51 by Bruno Berselli at Fri Apr 22 03:13:00 EDT 2016

STATUS

proposed

approved

#50 by Michel Marcus at Fri Apr 22 02:59:55 EDT 2016

STATUS

editing

proposed

#49 by Michel Marcus at Fri Apr 22 02:59:48 EDT 2016

LINKS

J. M. Thomas, <a href="http://dx.doi.org/10.1090/S0002-9904-1925-04036-7">The number of even and odd absolute permutations of n letters</a>, Bull. Amer. Math. Soc. 31 (1925), 303-304.

PROG

(PARI) a(n) = ( n!*sum(r=2, n, (-1)^r/r!) + (-1)^(n-1)*(n-1))/2; \\ Michel Marcus, Apr 22 2016

#48 by Michel Marcus at Fri Apr 22 02:55:24 EDT 2016

LINKS

L. Carlitz and R. A. Scoville, <a href="http://www.jstor.org/stable/2978096">Problem E2354</a>, Amer. Math. Monthly, 79 (1972), 394.

G. Gordon and E. McMahon, <a href="http://arxiv.org/abs/0906.4253">Moving faces to other places: facet derangements</a>, arXiv:0906.4253 [math.CO], 2009.

<a href="http://www.jstor.org/stable/2978096">Problem E2354</a>, Amer. Math. Monthly, 79 (1972), 394.

STATUS

approved

editing

#47 by Bruno Berselli at Tue Aug 11 10:37:08 EDT 2015

STATUS

reviewed

approved