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A376722
Expansion of 1/sqrt((1 - x^4 - x^5)^2 - 4*x^9).
3
1, 0, 0, 0, 1, 1, 0, 0, 1, 4, 1, 0, 1, 9, 9, 1, 1, 16, 36, 16, 2, 25, 100, 100, 26, 37, 225, 400, 226, 85, 442, 1225, 1226, 505, 833, 3137, 4901, 3217, 2080, 7120, 15878, 15976, 9081, 15696, 44182, 63626, 47125, 41625, 110926, 213688, 217801, 157300, 272251, 630458
OFFSET
0,10
FORMULA
a(n) = Sum_{k=0..floor(n/4)} binomial(k,n-4*k)^2.
PROG
(PARI) my(N=60, x='x+O('x^N)); Vec(1/sqrt((1-x^4-x^5)^2-4*x^9))
(PARI) a(n) = sum(k=0, n\4, binomial(k, n-4*k)^2);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 02 2024
STATUS
approved