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A376723
Expansion of 1/((1 - x^2 - x^3)^2 - 4*x^5).
5
1, 0, 2, 2, 3, 10, 7, 28, 33, 64, 132, 170, 408, 578, 1119, 2002, 3194, 6310, 10021, 18666, 32353, 55450, 101443, 170672, 308744, 534820, 935936, 1663892, 2872669, 5111652, 8898082, 15641802, 27538647, 48049562, 84813451, 148219128, 260572901, 457451088
OFFSET
0,3
FORMULA
a(n) = 2*a(n-2) + 2*a(n-3) - a(n-4) + 2*a(n-5) - a(n-6).
a(n) = (1/2) * Sum_{k=0..floor(n/2)} binomial(2*k+2,2*n-4*k+1).
PROG
(PARI) my(N=40, x='x+O('x^N)); Vec(1/((1-x^2-x^3)^2-4*x^5))
(PARI) a(n) = sum(k=0, n\2, binomial(2*k+2, 2*n-4*k+1))/2;
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 02 2024
STATUS
approved