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.

A294502 Binomial transform of A026007.

Original entry on oeis.org

1, 2, 5, 15, 45, 132, 381, 1086, 3060, 8531, 23563, 64560, 175639, 474790, 1275929, 3410180, 9068075, 23998671, 63230680, 165904474, 433596795, 1129037237, 2929620046, 7576584801, 19532878559, 50205938903, 128676829149, 328895341731, 838453003422
Offset: 0

Views

Author

Vaclav Kotesovec, Nov 01 2017

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 40; s = CoefficientList[Series[Product[(1+x^k)^k, {k, 1, nmax}], {x, 0, nmax}], x]; Table[Sum[Binomial[n, k] * s[[k+1]], {k, 0, n}], {n, 0, nmax}]

Formula

a(n) = Sum_{k=0..n} binomial(n,k) * A026007(k).
a(n) ~ exp(3^(4/3) * Zeta(3)^(1/3) * n^(2/3) / 4 + (3*Zeta(3))^(2/3) * n^(1/3) / 8 - Zeta(3)/16) * Zeta(3)^(1/6) * 2^(n - 1/12) / (3^(1/3) * sqrt(Pi) * n^(2/3)).
G.f.: (1/(1 - x))*Product_{k>=1} (1 + x^k/(1 - x)^k)^k. - Ilya Gutkovskiy, Aug 19 2018

A294501 Inverse binomial transform of the number of planar partitions (A000219).

Original entry on oeis.org

1, 0, 2, -1, 4, -7, 19, -48, 123, -304, 728, -1694, 3865, -8735, 19739, -44875, 102818, -236939, 546988, -1260023, 2888607, -6584008, 14927816, -33714166, 75976024, -171095098, 385405617, -868708176, 1959010348, -4417777937, 9957188242, -22420045445
Offset: 0

Views

Author

Vaclav Kotesovec, Nov 01 2017

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 40; s = CoefficientList[Series[Product[1/(1-x^k)^k, {k, 1, nmax}], {x, 0, nmax}], x]; Table[Sum[(-1)^(n-k) * Binomial[n, k] * s[[k+1]], {k, 0, n}], {n, 0, nmax}]

Formula

a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(n,k) * A000219(k).
G.f.: (1/(1 + x))*exp(Sum_{k>=1} sigma_2(k)*x^k/(k*(1 + x)^k)). - Ilya Gutkovskiy, Aug 20 2018

A294505 Inverse binomial transform of A156616.

Original entry on oeis.org

1, 1, 3, 3, 3, 7, -3, 13, -5, -7, 49, -97, 93, 155, -997, 2893, -5989, 9007, -7121, -10805, 63305, -169375, 321137, -418503, 152653, 1142657, -4565939, 11378145, -21893565, 32887315, -33140953, -1985517, 113177979, -348817177, 734074637, -1210600023
Offset: 0

Views

Author

Vaclav Kotesovec, Nov 01 2017

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 40; s = CoefficientList[Series[Product[((1+x^k)/(1-x^k))^k, {k, 1, nmax}], {x, 0, nmax}], x]; Table[Sum[(-1)^(n-k) * Binomial[n, k] * s[[k+1]], {k, 0, n}], {n, 0, nmax}]

Formula

a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(n,k) * A156616(k).
G.f.: (1/(1 + x))*exp(Sum_{k>=1} (sigma_2(2*k) - sigma_2(k))*x^k/(2*k*(1 + x)^k)). - Ilya Gutkovskiy, Oct 15 2018

A307260 Expansion of (1/(1 + x)) * Product_{k>=1} (1 + k*x^k/(1 + x)^k).

Original entry on oeis.org

1, 0, 1, 1, -4, 14, -35, 77, -161, 356, -873, 2267, -5787, 13850, -30361, 59934, -103754, 147968, -139049, -58998, 730972, -2430881, 6333238, -15548722, 39845197, -110775861, 325257904, -960503811, 2756222486, -7568564555, 19815541729, -49548068461, 118752506024
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 01 2019

Keywords

Comments

Inverse binomial transform of A022629.

Crossrefs

Programs

  • Maple
    a:=series((1/(1+x))*mul(1+k*x^k/(1+x)^k,k=1..100),x=0,33): seq(coeff(a,x,n),n=0..32); # Paolo P. Lava, Apr 03 2019
  • Mathematica
    nmax = 32; CoefficientList[Series[1/(1 + x) Product[(1 + k x^k/(1 + x)^k), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) = Sum_{k=0..n} (-1)^(n-k)*binomial(n,k)*A022629(k).
Showing 1-4 of 4 results.