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A366096
Expansion of (1/x) * Series_Reversion( x*(1+x-x^3)/(1+x)^3 ).
4
1, 2, 5, 15, 51, 187, 719, 2858, 11650, 48438, 204630, 875867, 3790172, 16554305, 72883035, 323109570, 1441152303, 6462494515, 29118219850, 131761291852, 598529262016, 2728346941040, 12476533435028, 57220220120080, 263125059775970, 1212942573227309
OFFSET
0,2
FORMULA
a(n) = (1/(n+1)) * Sum_{k=0..floor(n/3)} binomial(n+k,k) * binomial(2*n-k+2,n-3*k).
PROG
(PARI) a(n) = sum(k=0, n\3, binomial(n+k, k)*binomial(2*n-k+2, n-3*k))/(n+1);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Sep 29 2023
STATUS
approved