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.

A360890 G.f. satisfies A(x) = 1 + x/(1 - x^3) * A(x/(1 - x^3)).

Original entry on oeis.org

1, 1, 1, 1, 2, 4, 7, 12, 25, 55, 115, 245, 564, 1331, 3103, 7407, 18388, 46198, 116503, 299966, 789426, 2095941, 5616114, 15299205, 42255533, 117689096, 331204936, 944052610, 2718150015, 7891518587, 23137661717, 68524545717, 204645635263, 616098009473
Offset: 0

Views

Author

Seiichi Manyama, Feb 25 2023

Keywords

Crossrefs

Programs

  • PARI
    a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=0, (i-1)\3, binomial(i-1-2*j, j)*v[i-3*j])); v;

Formula

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

A360899 G.f. satisfies A(x) = 1 + x/(1 + x^4) * A(x/(1 + x^4)).

Original entry on oeis.org

1, 1, 1, 1, 1, 0, -2, -5, -9, -13, -10, 10, 60, 155, 281, 325, 5, -1214, -4094, -8786, -12571, -5642, 35339, 149264, 363838, 596714, 417156, -1373639, -7048541, -18932245, -34095357, -29271979, 68706873, 413250742, 1193425228, 2293494882, 2201716631
Offset: 0

Views

Author

Seiichi Manyama, Feb 25 2023

Keywords

Crossrefs

Programs

  • PARI
    a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=0, (i-1)\4, (-1)^j*binomial(i-1-3*j, j)*v[i-4*j])); v;

Formula

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

A360893 G.f. satisfies A(x) = 1 + x/(1 - x^4)^2 * A(x/(1 - x^4)).

Original entry on oeis.org

1, 1, 1, 1, 1, 3, 6, 10, 15, 24, 51, 109, 214, 389, 747, 1595, 3497, 7379, 15065, 31750, 70504, 159352, 353748, 777240, 1742696, 4022595, 9379659, 21717264, 50239529, 117913537, 281584044, 676667552, 1623733085, 3908144320, 9509212539, 23393422297, 57815808829
Offset: 0

Views

Author

Seiichi Manyama, Feb 25 2023

Keywords

Crossrefs

Programs

  • PARI
    a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=0, (i-1)\4, binomial(i-3*j, j)*v[i-4*j])); v;

Formula

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