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 1-4 of 4 results.

A381867 G.f. A(x) satisfies A(x) = C(x*A(x)) / (1 - x)^2, where C(x) is the g.f. of A000108.

Original entry on oeis.org

1, 3, 10, 44, 239, 1464, 9610, 65946, 466951, 3385259, 24999475, 187385168, 1421901090, 10901237530, 84312106160, 657031204068, 5153954345309, 40663760712441, 322478148002872, 2569086552458460, 20551321340065924, 165009872444132477, 1329352163579556971, 10742386009423170696
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(n+k+1, n-k)/(3*k+1));

Formula

a(n) = Sum_{k=0..n} binomial(3*k+1,k) * binomial(n+k+1,n-k)/(3*k+1).
a(n) = (1 + n)*hypergeom([1/3, 2/3, -n, 2+n], [1, 3/2, 3/2], -3^3/2^4). - Stefano Spezia, Mar 09 2025

A366215 G.f. A(x) satisfies A(x) = 1/(1 - x)^4 + x*(1 - x)^4*A(x)^4.

Original entry on oeis.org

1, 5, 26, 200, 1995, 22522, 272152, 3437280, 44806905, 598204475, 8137535934, 112382617018, 1571496538035, 22205618546014, 316570999534832, 4547819503936622, 65770112191659609, 956743348385310031, 13989838139093922658, 205511713513718581234
Offset: 0

Views

Author

Seiichi Manyama, Oct 04 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=0, n, binomial(n+7*k+3, n-k)*binomial(4*k, k)/(3*k+1));

Formula

a(n) = Sum_{k=0..n} binomial(n+7*k+3,n-k) * binomial(4*k,k)/(3*k+1).

A381944 G.f. A(x) satisfies A(x) = B(x*A(x)) / (1 - x)^3, where B(x) is the g.f. of A001764.

Original entry on oeis.org

1, 4, 16, 89, 655, 5592, 51594, 499159, 4990821, 51140527, 534152690, 5665496618, 60854697427, 660601882734, 7235771990454, 79870211543625, 887569516968685, 9921579561050637, 111487286796322366, 1258604967618419118, 14268057344239960863, 162358119295068686098
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(n+2*k+2, n-k)/(4*k+1));

Formula

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

A381947 G.f. A(x) satisfies A(x) = B(x*A(x)) / (1 - x)^3, where B(x) is the g.f. of A002293.

Original entry on oeis.org

1, 4, 17, 111, 1001, 10507, 118986, 1411789, 17307078, 217422098, 2784080234, 36201950786, 476725871599, 6344524132503, 85198695369123, 1152990558752089, 15708685673520617, 215287198676732925, 2965962577091646604, 41052101428818066604, 570583013508324005560
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(n+2*k+2, n-k)/(5*k+1));

Formula

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