The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A321633 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A321633

Number of permutations of the multiset {1,1,1,1,2,2,2,2,3,3,3,3,...,n,n,n,n} with no two consecutive terms equal.
(history; published version)

#27 by Hugo Pfoertner at Fri Sep 29 13:05:50 EDT 2023

STATUS

reviewed

approved

#26 by Stefano Spezia at Fri Sep 29 12:47:22 EDT 2023

STATUS

proposed

reviewed

#25 by Michel Marcus at Fri Sep 29 12:43:28 EDT 2023

STATUS

editing

proposed

#24 by Michel Marcus at Fri Sep 29 12:43:23 EDT 2023

FORMULA

a(n) = Integral_{0..infinityoo} (-x + 3/2 * x^2 - 1/2 * x^3 + 1/24 * x^4)^n * exp(-x) dx.

STATUS

approved

editing

#23 by Bruno Berselli at Tue Nov 27 11:37:30 EST 2018

STATUS

proposed

approved

#22 by Stefano Spezia at Tue Nov 27 11:26:41 EST 2018

STATUS

editing

proposed

#21 by Stefano Spezia at Tue Nov 27 11:26:38 EST 2018

MATHEMATICA

a[n_] := Integrate[(-x + 3/2 * x^2 - 1/2 * x^3 + 1/24 * x^4)^n * Exp[-x], {x, 0, Infinity}]; Array[a, 10, 0] (* Stefano Spezia, Nov 27 2018 *)

STATUS

proposed

editing

#20 by Seiichi Manyama at Tue Nov 27 06:54:01 EST 2018

STATUS

editing

proposed

#19 by Seiichi Manyama at Tue Nov 27 06:53:55 EST 2018

FORMULA

a(n) = Integral_{0..infinity} (-x + 3/2 * x^2 - 1/2 * x^3 + 1/24 * x^4)^n * exp(-x) dx.

STATUS

proposed

editing

#18 by Seiichi Manyama at Tue Nov 27 06:52:28 EST 2018

STATUS

editing

proposed