A241496 - OEIS

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A241496

Expansion of (1 + 4*x + x^2) / (1 - x^2)^3.

1, 4, 4, 12, 9, 24, 16, 40, 25, 60, 36, 84, 49, 112, 64, 144, 81, 180, 100, 220, 121, 264, 144, 312, 169, 364, 196, 420, 225, 480, 256, 544, 289, 612, 324, 684, 361, 760, 400, 840, 441, 924, 484, 1012, 529, 1104, 576, 1200, 625, 1300, 676, 1404, 729, 1512

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

COMMENTS

Column 3 of the table in A229834.

LINKS

Table of n, a(n) for n=0..53.

Index entries for linear recurrences with constant coefficients, signature (0,3,0,-3,0,1).

FORMULA

G.f.: (1 + 4*x + x^2) / (1 - x^2)^3. [Bruno Berselli, Apr 24 2014]

a(n) = a(-n-4) = 1 + ( 3*n*(n + 4) + 2 - (-1)^n*(n*(n + 4) + 2) )/8. [Bruno Berselli, Apr 24 2014]

MATHEMATICA