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A366098
Expansion of (1/x) * Series_Reversion( x*(1+x-x^4)/(1+x)^2 ).
2
1, 1, 1, 1, 2, 6, 16, 36, 76, 171, 427, 1111, 2841, 7096, 17722, 45124, 117078, 305906, 798526, 2083465, 5456182, 14373672, 38051106, 101006111, 268552030, 715329780, 1909982822, 5112653055, 13715017875, 36854688588, 99185583078, 267339331331, 721676892051
OFFSET
0,5
FORMULA
a(n) = (1/(n+1)) * Sum_{k=0..floor(n/4)} binomial(n+k,k) * binomial(n-k+1,n-4*k).
PROG
(PARI) a(n) = sum(k=0, n\4, binomial(n+k, k)*binomial(n-k+1, n-4*k))/(n+1);
CROSSREFS
Sequence in context: A157136 A178523 A270810 * A227035 A257198 A053210
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Sep 29 2023
STATUS
approved