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A376787
Expansion of (1 - x^2 + x^3)/((1 - x^2 + x^3)^2 - 4*x^3).
1
1, 0, 1, 3, 1, 10, 6, 21, 36, 43, 127, 139, 340, 540, 881, 1832, 2653, 5427, 8829, 15550, 28642, 46805, 87756, 147575, 262751, 465591, 797864, 1437816, 2471553, 4383696, 7689305, 13402819, 23752217, 41305842, 72916606, 127708213, 223809012, 394045411
OFFSET
0,4
FORMULA
a(n) = 2*a(n-2) + 2*a(n-3) - a(n-4) + 2*a(n-5) - a(n-6).
a(n) = Sum_{k=0..floor(n/2)} binomial(2*k+1,2*n-4*k).
PROG
(PARI) my(N=40, x='x+O('x^N)); Vec((1-x^2+x^3)/((1-x^2+x^3)^2-4*x^3))
(PARI) a(n) = sum(k=0, n\2, binomial(2*k+1, 2*n-4*k));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 04 2024
STATUS
approved