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URL: https://oeis.org/A376835

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A376835
Expansion of 1/((1-x)^4 - 8*x^4)^(1/4).
1
1, 1, 1, 1, 3, 11, 31, 71, 151, 343, 871, 2311, 6001, 15081, 37493, 94381, 241931, 625771, 1617211, 4164763, 10719793, 27674473, 71722773, 186353453, 484657729, 1260984161, 3283294561, 8559401761, 22343836711, 58391858383, 152722920691, 399719304411
OFFSET
0,5
FORMULA
a(n) = Sum_{k=0..floor(n/4)} (-8)^k * binomial(-1/4,k) * binomial(n,n-4*k).
(7 + 7*n)*a(n) + (7 + 4*n)*a(n + 1) - (15 + 6*n)*a(n + 2) + (13 + 4*n)*a(n + 3) - (n + 4)*a(n + 4) = 0. - Robert Israel, Oct 06 2024
MAPLE
f:= 1/((1-x)^4 - 8*x^4)^(1/4):
S:= series(f, x, 41):
seq(coeff(S, x, i), i=0..40); # Robert Israel, Oct 06 2024
MATHEMATICA
a[n_]:=Sum[(-8)^k * Binomial[-1/4, k] * Binomial[n, n-4*k], {k, 0, Floor[n/4]}]; Array[a, 32, 0] (* Stefano Spezia, Oct 06 2024 *)
PROG
(PARI) my(N=40, x='x+O('x^N)); Vec(1/((1-x)^4-8*x^4)^(1/4))
CROSSREFS
Cf. A004981.
Sequence in context: A093406 A393245 A379463 * A107587 A245931 A190590
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 06 2024
STATUS
approved