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A144904 Coefficient of x^n in expansion of x/((1-x-x^3)*(1-x)^(n-1)), also diagonal of A144903. 2
0, 1, 2, 6, 21, 76, 280, 1045, 3937, 14938, 56993, 218414, 840090, 3241153, 12537263, 48604755, 188799962, 734631798, 2862843281, 11171582151, 43647688211, 170720728344, 668414462009, 2619400928928, 10273572796046, 40325085206853, 158393604268277 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..500

FORMULA

a(n) = [x^n] x/((1-x-x^3)*(1-x)^(n-1)).

MAPLE

A:= proc(n, k) coeftayl (x/ (1-x-x^3)/ (1-x)^(k-1), x=0, n) end:

a:= n-> A(n, n):

seq(a(n), n=0..30);

# second Maple program:

a:= proc(n) option remember; `if`(n<3, n,

      ((27*n^3-150*n^2+195*n-12)*a(n-1)

      -(66*n^3-382*n^2+492*n+124)*a(n-2)

      +(27*n^3-156*n^2+201*n+48)*a(n-3)

      -2*(2*n-7)*(3*n^2-7*n-2)*a(n-4))/((n-1)*(3*n^2-13*n+8)))

    end:

seq(a(n), n=0..30);  # Alois P. Heinz, Jun 06 2013

CROSSREFS

Cf. A144903.

Sequence in context: A116821 A116772 A131792 * A151287 A294822 A294823

Adjacent sequences:  A144901 A144902 A144903 * A144905 A144906 A144907

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Sep 24 2008

STATUS

approved

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Last modified April 20 16:23 EDT 2021. Contains 343135 sequences. (Running on oeis4.)