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A376783
Expansion of 1/sqrt((1 - x^2 - x^5)^2 - 4*x^7).
1
1, 0, 1, 0, 1, 1, 1, 4, 1, 9, 2, 16, 10, 25, 37, 37, 101, 65, 226, 164, 443, 481, 810, 1325, 1522, 3258, 3251, 7236, 7926, 15010, 20234, 30557, 50234, 64501, 117966, 145557, 263107, 346293, 569726, 835909, 1233943, 1984730, 2740492, 4579704, 6288323, 10311571
OFFSET
0,8
FORMULA
G.f.: 1/sqrt((1 - x^2 + x^5)^2 - 4*x^5) = 1/sqrt((1 + x^2 - x^5)^2 - 4*x^2).
PROG
(PARI) my(N=50, x='x+O('x^N)); Vec(1/sqrt((1-x^2-x^5)^2-4*x^7))
(PARI) a(n) = sum(k=0, n\5, ((n-3*k)%2==0)*binomial((n-3*k)/2, k)^2);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 04 2024
STATUS
approved