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 1-6 of 6 results.

A365119 G.f. satisfies A(x) = (1 + x / (1 - x*A(x)))^3.

Original entry on oeis.org

1, 3, 6, 19, 69, 267, 1093, 4629, 20142, 89473, 404076, 1849746, 8563558, 40025574, 188612388, 895115942, 4274453904, 20523807009, 99025615998, 479874362583, 2334582421497, 11398055887003, 55828060595832, 274254002718255, 1350907899813921, 6670789629569022
Offset: 0

Views

Author

Seiichi Manyama, Aug 22 2023

Keywords

Crossrefs

Programs

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

Formula

If g.f. satisfies A(x) = (1 + x/(1 - x*A(x))^s)^t, then a(n) = Sum_{k=0..n} binomial(t*(n-k+1),k) * binomial(n+(s-1)*k-1,n-k)/(n-k+1).

A371612 G.f. satisfies A(x) = ( 1 + x / (1 - x*A(x)^2) )^2.

Original entry on oeis.org

1, 2, 3, 12, 49, 218, 1037, 5106, 25909, 134410, 709691, 3801498, 20606654, 112828202, 623087675, 3466539248, 19411070496, 109313442562, 618713495451, 3517737628368, 20081523836403, 115058714898196, 661432784830204, 3813891082337178, 22052422636145522
Offset: 0

Views

Author

Seiichi Manyama, Mar 29 2024

Keywords

Crossrefs

Programs

  • PARI
    a(n, r=2, s=1, t=0, u=4) = r*sum(k=0, n, binomial(t*k+u*(n-k)+r, k)*binomial(n+(s-1)*k-1, n-k)/(t*k+u*(n-k)+r));

Formula

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

A365120 G.f. A(x) satisfies A(x) = (1 + x / (1 - x*A(x))^2)^2.

Original entry on oeis.org

1, 2, 5, 18, 70, 294, 1291, 5864, 27314, 129766, 626367, 3063096, 15143562, 75563924, 380062186, 1924840480, 9807649900, 50241194250, 258597717591, 1336730670244, 6936403057274, 36119232561000, 188677598254078, 988464846388710, 5192270327405662
Offset: 0

Views

Author

Seiichi Manyama, Aug 22 2023

Keywords

Crossrefs

Programs

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

Formula

If g.f. satisfies A(x) = (1 + x/(1 - x*A(x))^s)^t, then a(n) = Sum_{k=0..n} binomial(t*(n-k+1),k) * binomial(n+(s-1)*k-1,n-k)/(n-k+1).
G.f.: A(x) = B(x)^2 where B(x) is the g.f. of A367236. - Seiichi Manyama, Dec 06 2024

A371613 G.f. satisfies A(x) = ( 1 + x / (1 - x*A(x)^3) )^2.

Original entry on oeis.org

1, 2, 3, 16, 83, 460, 2767, 17210, 110308, 723624, 4832363, 32747106, 224619408, 1556484636, 10879744696, 76621739626, 543159825499, 3872610857558, 27752175177823, 199787917082084, 1444171829169939, 10477887409768628, 76275565075016394
Offset: 0

Views

Author

Seiichi Manyama, Mar 29 2024

Keywords

Crossrefs

Programs

  • PARI
    a(n, r=2, s=1, t=0, u=6) = r*sum(k=0, n, binomial(t*k+u*(n-k)+r, k)*binomial(n+(s-1)*k-1, n-k)/(t*k+u*(n-k)+r));

Formula

a(n) = Sum_{k=0..n} binomial(6*(n-k)+2,k) * binomial(n-1,n-k)/(3*(n-k)+1).

A378801 G.f. A(x) satisfies A(x) = ( 1 + x/(1 - x*A(x)^(2/3)) )^3.

Original entry on oeis.org

1, 3, 6, 16, 48, 153, 511, 1761, 6219, 22383, 81804, 302766, 1132475, 4274166, 16256685, 62249167, 239772510, 928398831, 3611539758, 14107963848, 55318781982, 217652858539, 859027927911, 3400055112777, 13492710661658, 53673238384560, 213984657134418
Offset: 0

Views

Author

Seiichi Manyama, Dec 09 2024

Keywords

Crossrefs

Programs

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

Formula

G.f. A(x) satisfies A(x) = 1 + x * (1 + A(x)^(1/3) + A(x)^(5/3)).
G.f.: A(x) = (1 + x*B(x))^3 where B(x) is the g.f. of A161634.
If g.f. satisfies A(x) = ( 1 + x*A(x)^(t/r) / (1 - x*A(x)^(u/r))^s )^r, then a(n) = r * Sum_{k=0..n} binomial(t*k+u*(n-k)+r,k) * binomial(n+(s-1)*k-1,n-k)/(t*k+u*(n-k)+r).

A378732 G.f. A(x) satisfies A(x) = ( 1 + x / (1 - x*A(x)) )^4.

Original entry on oeis.org

1, 4, 10, 36, 155, 704, 3384, 16844, 86097, 449344, 2384170, 12822556, 69743953, 382982940, 2120323014, 11822279232, 66327376437, 374162700460, 2120999728610, 12075668658000, 69021358842795, 395909382981572, 2278286453089574, 13149207655326372, 76096242994616990
Offset: 0

Views

Author

Seiichi Manyama, Dec 05 2024

Keywords

Crossrefs

Programs

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

Formula

G.f.: A(x) = (1 + x*B(x))^4 where B(x) is the g.f. of A364743.
If g.f. satisfies A(x) = ( 1 + x*A(x)^(t/r) / (1 - x*A(x)^(u/r))^s )^r, then a(n) = r * Sum_{k=0..n} binomial(t*k+u*(n-k)+r,k) * binomial(n+(s-1)*k-1,n-k)/(t*k+u*(n-k)+r).
Showing 1-6 of 6 results.