A367050 G.f. satisfies A(x) = 1 + x*A(x)^4 + x^2*A(x)^3.

1, 1, 5, 29, 198, 1469, 11518, 93875, 787392, 6752175, 58929541, 521718814, 4674070602, 42296077935, 386027716280, 3549332631052, 32845586854208, 305685481682970, 2859315003009776, 26866125820982711, 253457922829307765, 2399910588283502630

Offset

0,3

Links

Table of n, a(n) for n=0..21.

Formula

a(n) = Sum_{k=0..floor(n/2)} binomial(3*n-3*k+1,k) * binomial(4*n-5*k,n-2*k)/(3*n-3*k+1).

Prog

(PARI) a(n) = sum(k=0, n\2, binomial(3*n-3*k+1, k)*binomial(4*n-5*k, n-2*k)/(3*n-3*k+1));

Crossrefs

Cf. A365178, A365180, A365181, A365182, A365183, A367041, A367048, A367049.

Sequence in context: A201115 A199419 A094710 * A216313 A108453 A201203

Adjacent sequences: A367047 A367048 A367049 * A367051 A367052 A367053

Keyword

nonn

Author

Seiichi Manyama, Nov 03 2023

Status

approved