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A365693
G.f. satisfies A(x) = 1 + x*A(x) / (1 - x^2*A(x)^5).
3
1, 1, 1, 2, 8, 30, 103, 368, 1407, 5531, 21905, 87689, 355929, 1461022, 6046160, 25194331, 105661615, 445692621, 1889454880, 8045796200, 34398989998, 147606568810, 635481458969, 2744158752772, 11882687400375, 51584960268914, 224465280616995, 978851595046223
OFFSET
0,4
FORMULA
a(n) = Sum_{k=0..floor(n/2)} binomial(n-k-1,k) * binomial(n+3*k+1,n-2*k) / (n+3*k+1).
PROG
(PARI) a(n) = sum(k=0, n\2, binomial(n-k-1, k)*binomial(n+3*k+1, n-2*k)/(n+3*k+1));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Sep 16 2023
STATUS
approved