cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A381860 G.f. A(x) satisfies A(x) = (1 + x)^3 * C(x*A(x)), where C(x) is the g.f. of A000108.

Original entry on oeis.org

1, 4, 12, 55, 327, 2157, 15141, 110853, 836790, 6465309, 50876776, 406335099, 3285202335, 26835060422, 221128733649, 1835973630276, 15344202894457, 128983332603009, 1089803313492966, 9250137181234430, 78837133437062307, 674408139329393187, 5788618956395607745
Offset: 0

Views

Author

Seiichi Manyama, Mar 08 2025

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n, binomial(3*k+1, k)*binomial(3*k+3, n-k)/(3*k+1));

Formula

a(n) = Sum_{k=0..n} binomial(3*k+1,k) * binomial(3*k+3,n-k)/(3*k+1).
D-finite with recurrence -2*n*(2*n+1)*a(n) +3*(n^2+13*n-6)*a(n-1) +3*(69*n^2-221*n+150)*a(n-2) +2*(397*n^2-2431*n+3471)*a(n-3) +6*(225*n^2-1953*n+4079)*a(n-4) +9*(135*n^2-1503*n+4084)*a(n-5) +9*(63*n^2-855*n+2860)*a(n-6) +12*(3*n-22)*(3*n-26)*a(n-7)=0. - R. J. Mathar, Mar 10 2025

A381937 G.f. A(x) satisfies A(x) = (1 + x) * B(x*A(x)), where B(x) is the g.f. of A001764.

Original entry on oeis.org

1, 2, 6, 35, 240, 1805, 14386, 119365, 1020136, 8918423, 79380514, 716911887, 6553219720, 60513355786, 563648995020, 5289485238552, 49963186247220, 474655663418546, 4532279676629700, 43473774550929628, 418706702628897708, 4047555977981218963
Offset: 0

Views

Author

Seiichi Manyama, Mar 10 2025

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n, binomial(4*k+1, k)*binomial(k+1, n-k)/(4*k+1));

Formula

a(n) = Sum_{k=0..n} binomial(4*k+1,k) * binomial(k+1,n-k)/(4*k+1).
a(n) = A365178(n) + A365178(n-1).

A381940 G.f. A(x) satisfies A(x) = (1 + x) * B(x*A(x)), where B(x) is the g.f. of A002293.

Original entry on oeis.org

1, 2, 7, 51, 440, 4170, 41921, 438972, 4736281, 52286520, 587774685, 6705201456, 77426676892, 903251324476, 10629495065550, 126032922655030, 1504194199010435, 18056321542477095, 217859030049153565, 2640609137351540510, 32137554969392230950, 392580762083089376630
Offset: 0

Views

Author

Seiichi Manyama, Mar 10 2025

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n, binomial(5*k+1, k)*binomial(k+1, n-k)/(5*k+1));

Formula

a(n) = Sum_{k=0..n} binomial(5*k+1,k) * binomial(k+1,n-k)/(5*k+1).
a(n) = A365184(n) + A365184(n-1).
Showing 1-3 of 3 results.