

A163941


Fourth right hand column of triangle A163940.


4



1, 9, 52, 246, 1039, 4083, 15274, 55152, 193957, 668397, 2266816, 7589418, 25143355, 82571751, 269173078, 871958244, 2809322833, 9008574945, 28768068460, 91532284830, 290283189991, 917912770779, 2894936303362
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OFFSET

0,2


LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000
Harry Crane, Leftright arrangements, set partitions, and pattern avoidance, Australasian Journal of Combinatorics, 61(1) (2015), 5772.
Index entries for linear recurrences with constant coefficients, signature (9,29,39,18).


FORMULA

G.f.: 1/((1x)*(12*x)*(13*x)^2).
a(n) = (1/4)*(2^(n+5) + (2*n  3)*3^(n+2)  1).
a(n) = 9*a(n1)  29*a(n2) + 39*a(n3)  18*a(n4).
E.g.f.: (1/4)*(32*exp(2*x) + 27*(2*x1)*exp(3*x)  exp(x)).  G. C. Greubel, Aug 13 2017


MATHEMATICA

LinearRecurrence[{9, 29, 39, 18}, {1, 9, 52, 246}, 30] (* or *) CoefficientList[ Series[1/((1x)(12x)(13x)^2), {x, 0, 30}], x] (* Harvey P. Dale, Aug 14 2011 *)


PROG

(PARI) Vec(1/((1x)*(12*x)*(13*x)^2) + O(x^30)) \\ Michel Marcus, Feb 12 2015


CROSSREFS

Equals the fourth right hand column of A163940.
A163942 is another right hand column.
Sequence in context: A197722 A172470 A120665 * A289418 A292488 A282179
Adjacent sequences: A163938 A163939 A163940 * A163942 A163943 A163944


KEYWORD

easy,nonn


AUTHOR

Johannes W. Meijer, Aug 13 2009


STATUS

approved



