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.

A320235 G.f.: Product_{k>=1, j>=1} (1 + x^(k*j))^2.

Original entry on oeis.org

1, 2, 5, 12, 24, 48, 94, 172, 310, 550, 946, 1602, 2679, 4394, 7123, 11424, 18082, 28344, 44039, 67754, 103412, 156660, 235489, 351602, 521650, 768998, 1127100, 1642946, 2381929, 3436028, 4932998, 7049004, 10028422, 14207122, 20044327, 28169528, 39439899
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 08 2018

Keywords

Comments

Self-convolution of A107742.

Crossrefs

Programs

  • Mathematica
    nmax = 50; CoefficientList[Series[Product[(1+x^(k*j))^2, {k, 1, nmax}, {j, 1, Floor[nmax/k] + 1}], {x, 0, nmax}], x]

Formula

Conjecture: log(a(n)) ~ Pi*sqrt(n*log(n)/3).

A320238 G.f.: Product_{k>=1, j>=1} (1 + x^(k*j)) / (1 - x^(k*j))^2.

Original entry on oeis.org

1, 3, 11, 31, 85, 209, 504, 1138, 2514, 5339, 11098, 22432, 44535, 86523, 165496, 311187, 577190, 1055524, 1907423, 3405574, 6016826, 10520065, 18222215, 31275320, 53230224, 89860112, 150551503, 250388180, 413572707, 678574627, 1106396434, 1793009335
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 08 2018

Keywords

Comments

Convolution of A107742 and A320236.

Crossrefs

Programs

  • Mathematica
    nmax = 50; CoefficientList[Series[Product[(1+x^(k*j))/(1-x^(k*j))^2, {k, 1, nmax}, {j, 1, Floor[nmax/k] + 1}], {x, 0, nmax}], x]

Formula

Conjecture: log(a(n)) ~ Pi * sqrt(5*n*log(n)/6).

A320237 G.f.: Product_{k>=1, j>=1} ((1 + x^(k*j)) / (1 - x^(k*j)))^2.

Original entry on oeis.org

1, 4, 16, 52, 156, 428, 1120, 2772, 6616, 15224, 34032, 74020, 157340, 327244, 667824, 1338828, 2641332, 5133372, 9840432, 18621476, 34818852, 64374564, 117768176, 213306948, 382733816, 680630120, 1200198784, 2099417544, 3644332860, 6280017740, 10746594208
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 08 2018

Keywords

Comments

Self-convolution of A301554.
Convolution of A320235 and A320236.

Crossrefs

Programs

  • Mathematica
    nmax = 40; CoefficientList[Series[Product[((1+x^(k*j))/(1-x^(k*j)))^2, {k, 1, nmax}, {j, 1, Floor[nmax/k] + 1}], {x, 0, nmax}], x]

Formula

Conjecture: log(a(n)) ~ Pi * sqrt(n*log(n)).

A320245 G.f.: Product_{k>=1, j>=1} 1/((1 + x^(k*j)) * (1 - x^(k*j))^2).

Original entry on oeis.org

1, 1, 4, 6, 17, 25, 59, 89, 187, 284, 545, 828, 1505, 2270, 3930, 5904, 9861, 14695, 23827, 35248, 55775, 81882, 126874, 184870, 281467, 407065, 610193, 876282, 1295892, 1848144, 2700398, 3825912, 5530337, 7786022, 11145541, 15597196, 22131170, 30792303
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 08 2018

Keywords

Comments

Convolution of A288007 and A320236.

Crossrefs

Programs

  • Mathematica
    nmax = 50; CoefficientList[Series[Product[1/((1+x^(k*j))*(1-x^(k*j))^2), {k, 1, nmax}, {j, 1, Floor[nmax/k]+1}], {x, 0, nmax}], x]
Showing 1-4 of 4 results.