The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A279563 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A279563

Number of length n inversion sequences avoiding the patterns 102, 201, and 210.
(history; published version)

#14 by Vaclav Kotesovec at Thu Oct 07 04:10:29 EDT 2021

STATUS

editing

approved

#13 by Vaclav Kotesovec at Thu Oct 07 04:10:14 EDT 2021

FORMULA

a(n) ~ 4^n / (3*sqrt(Pi*n)). - Vaclav Kotesovec, Oct 07 2021

STATUS

approved

editing

#12 by Bruno Berselli at Mon Nov 06 08:52:53 EST 2017

STATUS

proposed

approved

#11 by Jean-François Alcover at Mon Nov 06 07:44:00 EST 2017

STATUS

editing

proposed

#10 by Jean-François Alcover at Mon Nov 06 07:43:29 EST 2017

MATHEMATICA

a[n_] := a[n] = If[n < 4, n!, ((2*(12*n^3 - 91*n^2 + 213*n - 149))*a[n-1] - (3*(21*n^3 - 162*n^2 + 392*n - 291))*a[n-2] + (2*(33*n^3 - 257*n^2 + 633*n - 484))*a[n-3] - (4*(2*n - 7))*(3*n^2 - 13*n + 13)*a[n-4]) / ((n - 1)*(3*n^2 - 19*n + 29))]; Array[a, 30, 0] (* Jean-François Alcover, Nov 06 2017, after Alois P. Heinz *)

STATUS

approved

editing

#9 by Alois P. Heinz at Wed Feb 22 16:08:12 EST 2017

STATUS

editing

approved

#8 by Alois P. Heinz at Wed Feb 22 16:06:49 EST 2017

LINKS

Alois P. Heinz, <a href="/A279563/b279563.txt">Table of n, a(n) for n = 0..1664</a>

MAPLE

a:= proc(n) option remember; `if`(n<4, n!,

((2*(12*n^3-91*n^2+213*n-149))*a(n-1)

-(3*(21*n^3-162*n^2+392*n-291))*a(n-2)

+(2*(33*n^3-257*n^2+633*n-484))*a(n-3)

-(4*(2*n-7))*(3*n^2-13*n+13)*a(n-4))

/ ((n-1)*(3*n^2-19*n+29)))

end:

seq(a(n), n=0..30); # Alois P. Heinz, Feb 22 2017

#7 by Alois P. Heinz at Wed Feb 22 15:44:07 EST 2017

KEYWORD

nonn,more,new

EXTENSIONS

a(10)-a(26) from Alois P. Heinz, Feb 22 2017

#6 by Alois P. Heinz at Wed Feb 22 15:43:32 EST 2017

DATA

1, 1, 2, 6, 22, 85, 328, 1253, 4754, 17994, 68158, 258808, 985906, 3768466, 14451386, 55585014, 214377618, 828795169, 3211030684, 12464308997, 48465092366, 188733879657, 735977084412, 2873525548315, 11231884145434, 43947466923095, 172115939825516

#5 by Alois P. Heinz at Wed Feb 22 15:31:02 EST 2017

DATA

1, 1, 2, 6, 22, 85, 328, 1253, 4754, 17994, 68158

STATUS

approved

editing