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.

A368525 a(n) = Sum_{k=1..n} k^3 * n^(n-k).

Original entry on oeis.org

0, 1, 10, 60, 364, 2745, 27246, 346864, 5422264, 100449225, 2149062490, 52097910876, 1410401518692, 42153624499441, 1378058477508454, 48900582823143360, 1871456346915007216, 76821658841556480753, 3366451935514051046802, 156839738363103277783900
Offset: 0

Views

Author

Seiichi Manyama, Dec 28 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=1, n, k^3*n^(n-k));

Formula

a(n) = [x^n] x * (1+4*x+x^2)/((1-n*x) * (1-x)^4).
a(n) = n * (n^n * (n^2 + 4*n + 1) - n^5 - 3*n^2 - n - 1)/(n-1)^4 for n > 1.

A368526 a(n) = Sum_{k=1..n} k^2 * n^k.

Original entry on oeis.org

0, 1, 18, 282, 4740, 89355, 1896846, 45050852, 1186829064, 34391135205, 1087928669410, 37322190255966, 1380461544684300, 54772368958008975, 2320775754168090870, 104596636848116060040, 4996700995031905899536, 252208510175779038669321
Offset: 0

Views

Author

Seiichi Manyama, Dec 28 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=1, n, k^2*n^k);

Formula

a(n) = [x^n] n*x * (1+n*x)/((1-x) * (1-n*x)^3).
a(n) = n * (n+1) * (n^n * (n^3-3*n^2+2*n+1) - 1)/(n-1)^3 for n > 1.

A368529 a(n) = Sum_{k=1..n} k^2 * 4^(n-k).

Original entry on oeis.org

0, 1, 8, 41, 180, 745, 3016, 12113, 48516, 194145, 776680, 3106841, 12427508, 49710201, 198841000, 795364225, 3181457156, 12725828913, 50903315976, 203613264265, 814453057460, 3257812230281, 13031248921608, 52124995686961, 208499982748420, 833999930994305
Offset: 0

Views

Author

Seiichi Manyama, Dec 28 2023

Keywords

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{7, -15, 13, -4}, {0, 1, 8, 41}, 30] (* Paolo Xausa, Jan 29 2024 *)
  • PARI
    a(n) = sum(k=1, n, k^2*4^(n-k));

Formula

G.f.: x * (1+x)/((1-4*x) * (1-x)^3).
a(n) = 7*a(n-1) - 15*a(n-2) + 13*a(n-3) - 4*a(n-4).
a(n) = A052161(n-1) + A052161(n-2) for n > 1.
a(n) = (5*4^(n+1) - (9*n^2 + 24*n + 20))/27.
a(0) = 0; a(n) = 4*a(n-1) + n^2.

A368528 a(n) = Sum_{k=1..n} k^2 * 3^(n-k).

Original entry on oeis.org

0, 1, 7, 30, 106, 343, 1065, 3244, 9796, 29469, 88507, 265642, 797070, 2391379, 7174333, 21523224, 64569928, 193710073, 581130543, 1743391990, 5230176370, 15690529551, 47071589137, 141214767940, 423644304396, 1270932913813, 3812798742115
Offset: 0

Views

Author

Seiichi Manyama, Dec 28 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = sum(k=1, n, k^2*3^(n-k));

Formula

G.f.: x * (1+x)/((1-3*x) * (1-x)^3).
a(n) = 6*a(n-1) - 12*a(n-2) + 10*a(n-3) - 3*a(n-4).
a(n) = A052150(n-1) + A052150(n-2) for n > 1.
a(n) = (3^(n+1) - (n^2 + 3*n + 3))/2.
a(0) = 0; a(n) = 3*a(n-1) + n^2.
Showing 1-4 of 4 results.