A077922 - OEIS

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A077922

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

1, -1, 4, -9, 24, -60, 154, -391, 997, -2538, 6465, -16464, 41932, -106792, 271981, -692685, 1764144, -4492953, 11442736, -29142568, 74220826, -189026955, 481417305, -1226082390, 3122609041, -7952717776, 20254126984, -51583580784, 131374006329, -334585720425, 852129027964

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OFFSET

0,3

LINKS

Table of n, a(n) for n=0..30.

Index entries for linear recurrences with constant coefficients, signature (-1,3,-2,1)

FORMULA

a(n) = (1 + 2*A077986(n) + A077986(n-2))/3. - R. J. Mathar

MAPLE

A077986 := proc(n) if n < 0 then 0; else coeftayl( 1/(1+2*x-x^2+x^3), x=0, n) ; end if; end proc:

A077922 := proc(n) (1+2*A077986(n)+A077986(n-2))/3 ; end proc:

seq(A077922(n), n=0..20) ; # R. J. Mathar, Mar 24 2011