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 1-2 of 2 results.

A378152 G.f. A(x) satisfies A(x) = 1 + (x * (1+x) * A(x))^4.

Original entry on oeis.org

1, 0, 0, 0, 1, 4, 6, 4, 5, 32, 112, 224, 302, 488, 1564, 4872, 11034, 19664, 37128, 95824, 266659, 635740, 1306682, 2706524, 6503711, 16794992, 40634744, 90066416, 197648134, 465436936, 1152867388, 2790870536, 6434526866, 14640368240, 34415925816, 83509570992
Offset: 0

Views

Author

Seiichi Manyama, Nov 18 2024

Keywords

Crossrefs

Programs

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

Formula

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

A378153 G.f. A(x) satisfies A(x) = 1 + (x * (1+x))^3 * A(x)^2.

Original entry on oeis.org

1, 0, 0, 1, 3, 3, 3, 12, 30, 45, 75, 192, 436, 798, 1554, 3542, 7740, 15543, 32183, 70794, 153252, 321431, 684123, 1491504, 3232672, 6928779, 14957787, 32615388, 70991040, 153985890, 335256886, 733206840, 1603258134, 3503385568, 7671749664, 16837946850
Offset: 0

Views

Author

Seiichi Manyama, Nov 18 2024

Keywords

Crossrefs

Programs

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

Formula

a(n) = Sum_{k=0..floor(n/3)} binomial(3*k,n-3*k) * C(k), where C(k) are the Catalan numbers (A000108).
G.f.: 2/(1 + sqrt(1 - 4*(x*(1+x))^3)).
Showing 1-2 of 2 results.