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A369443 Expansion of (1/x) * Series_Reversion( x / ((1+x)^2 * (1+x^3)) ). 2
1, 2, 5, 15, 52, 198, 796, 3306, 14042, 60698, 266235, 1182315, 5306085, 24028162, 109654887, 503797703, 2328343326, 10816971516, 50487762906, 236635814984, 1113297830297, 5255647026534, 24888156618738, 118194065746758, 562773777767295, 2686074452484012 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
a(n) = (1/(n+1)) * Sum_{k=0..floor(n/3)} binomial(n+1,k) * binomial(2*n+2,n-3*k).
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x/((1+x)^2*(1+x^3)))/x)
(PARI) a(n, s=3, t=1, u=2) = sum(k=0, n\s, binomial(t*(n+1), k)*binomial(u*(n+1), n-s*k))/(n+1);
CROSSREFS
Cf. A198951.
Sequence in context: A287276 A361762 A367415 * A369398 A370798 A007312
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jan 23 2024
STATUS
approved

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Last modified June 23 11:44 EDT 2024. Contains 373644 sequences. (Running on oeis4.)