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.

A356270 a(n) = Sum_{k=0..n} binomial(2*k, k) * q(k), where q(k) is the number of partitions into distinct parts (A000009).

Original entry on oeis.org

1, 3, 9, 49, 189, 945, 4641, 21801, 99021, 487981, 2335541, 10800725, 51363065, 238573865, 1121139065, 5309312105, 24543884585, 113220920945, 530677144745, 2439321389945, 11261499234425, 52169097691865, 239433905462945, 1095710701133345, 5029918350471545
Offset: 0

Views

Author

Vaclav Kotesovec, Aug 01 2022

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[Binomial[2*k, k] * PartitionsQ[k], {k, 0, n}], {n, 0, 30}]

Formula

a(n) ~ binomial(2*n,n) * q(n) * 4/3.
a(n) ~ 2^(2*n) * exp(Pi*sqrt(n/3)) / (3^(5/4) * sqrt(Pi) * n^(5/4)).

A356286 a(n) = Sum_{k=0..n} binomial(3*k, k) * p(k), where p(k) is the partition function A000041.

Original entry on oeis.org

1, 4, 34, 286, 2761, 23782, 227986, 1972186, 18152548, 158757298, 1420647928, 12258704248, 108637887148, 929002856992, 8065133782792, 68761800685576, 589631899738033, 4976639418495358, 42293283621258283, 354415428588891283, 2982701933728936648, 24857294772400460368
Offset: 0

Views

Author

Vaclav Kotesovec, Aug 01 2022

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[Binomial[3*k, k] * PartitionsP[k], {k, 0, n}], {n, 0, 30}]
  • PARI
    a(n) = sum(k=0, n, binomial(3*k, k)*numbpart(k)); \\ Michel Marcus, Aug 02 2022

Formula

a(n) ~ 3^(3*n+3) * exp(Pi*sqrt(2*n/3)) / (23 * sqrt(Pi) * n^(3/2) * 2^(2*n+3)).

A367100 a(n) = Sum_{k=0..n} A000108(k) * A000041(k).

Original entry on oeis.org

1, 2, 6, 21, 91, 385, 1837, 8272, 39732, 185592, 891024, 4183040, 20199964, 95232864, 456282264, 2162574984, 10330196754, 48834699384, 232725598884, 1098684561984, 5214388065324, 24591671545164, 116257200312444, 546797015443194, 2578396047478494, 12098087101521510
Offset: 0

Views

Author

Vaclav Kotesovec, Nov 04 2023

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[CatalanNumber[k]*PartitionsP[k], {k, 0, n}], {n, 0, 30}]

Formula

a(n) ~ 2^(2*n) * exp(Pi*sqrt(2*n/3)) / (3^(3/2) * sqrt(Pi) * n^(5/2)).
Showing 1-3 of 3 results.