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A364337
G.f. satisfies A(x) = (1 + x) * (1 + x*A(x)^4).
9
1, 2, 9, 68, 580, 5406, 53270, 545844, 5757332, 62094217, 681653493, 7591431752, 85558696024, 974024788280, 11184192097016, 129378232148016, 1506363564912368, 17639001584452320, 207593804132718948, 2454236122156830254, 29132714097692056954, 347086786035103983446
OFFSET
0,2
LINKS
FORMULA
a(n) = Sum_{k=0..n} binomial(4*k+1,k) * binomial(4*k+1,n-k) / (4*k+1).
PROG
(PARI) a(n) = sum(k=0, n, binomial(4*k+1, k)*binomial(4*k+1, n-k)/(4*k+1));
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jul 19 2023
STATUS
approved