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.

A294500 Binomial transform of the number of planar partitions (A000219).

Original entry on oeis.org

1, 2, 6, 19, 60, 185, 559, 1662, 4875, 14134, 40564, 115370, 325465, 911355, 2534595, 7004827, 19246626, 52596377, 143006632, 386984573, 1042537831, 2796803110, 7473161196, 19893461042, 52767059608, 139488323734, 367540167625, 965445514862, 2528516552660
Offset: 0

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Author

Vaclav Kotesovec, Nov 01 2017

Keywords

Comments

Let 0 < p < 1, r > 0, v > 0, f(n) = v*exp(r*n^p)/n^b, then
Sum_{k=0..n} binomial(n,k) * f(k) ~ f(n/2) * 2^n * exp(g(n)), where
g(n) = p^2 * r^2 * n^p / (2^(1+2*p)*n^(1-p) + p*r*(1-p)*2^(1+p)).
Special cases:
p < 1/2, g(n) = 0
p = 1/2, g(n) = r^2/16
p = 2/3, g(n) = r^2 * n^(1/3) / (9 * 2^(1/3)) - r^3/81
p = 3/4, g(n) = 9*r^2*sqrt(n)/(64*sqrt(2)) - 27*r^3*n^(1/4)/(2048*2^(1/4)) + 81*r^4/65536
p = 3/5, g(n) = 9*r^2*n^(1/5)/(100*2^(1/5))
p = 4/5, g(n) = 2^(7/5)*r^2*n^(3/5)/25 - 4*2^(3/5)*r^3*n^(2/5)/625 + 8*2^(4/5)*r^4*n^(1/5)/15625 - 32*r^5/390625

Crossrefs

Programs

  • Mathematica
    nmax = 40; s = CoefficientList[Series[Product[1/(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) * A000219(k).
a(n) ~ exp(1/12 + 3 * Zeta(3)^(1/3) * n^(2/3) / 2^(4/3) + Zeta(3)^(2/3) * n^(1/3) / 2^(5/3) - Zeta(3)/12) * 2^(n + 7/18) * Zeta(3)^(7/36) / (A * sqrt(3*Pi) * n^(25/36)), where A is the Glaisher-Kinkelin constant A074962.
G.f.: (1/(1 - x))*exp(Sum_{k>=1} sigma_2(k)*x^k/(k*(1 - x)^k)). - Ilya Gutkovskiy, Aug 20 2018

A294503 Inverse binomial transform of A026007.

Original entry on oeis.org

1, 0, 1, 1, -3, 10, -23, 48, -92, 171, -321, 626, -1265, 2576, -5099, 9478, -15925, 22617, -21816, -8506, 121659, -436121, 1204710, -2962759, 6860591, -15427559, 34323613, -76269455, 169591278, -376162414, 827819644, -1798045927, 3839392935, -8041078328
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[(-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) * A026007(k).
G.f.: (1/(1 + x))*Product_{k>=1} (1 + x^k/(1 + x)^k)^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

A307258 Expansion of (1/(1 + x)) * Product_{k>=1} 1/(1 - k*x^k/(1 + x)^k).

Original entry on oeis.org

1, 0, 2, -1, 5, -11, 36, -107, 311, -850, 2208, -5519, 13566, -33562, 84937, -220307, 579413, -1522616, 3954016, -10100863, 25416877, -63324271, 157248035, -391478354, 980410093, -2470810086, 6253495883, -15846525758, 40093721908, -101116823798, 254093749587, -636547773777
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 01 2019

Keywords

Comments

Inverse binomial transform of A006906.

Crossrefs

Programs

  • Maple
    a:=series((1/(1+x))*mul(1/(1-k*x^k/(1+x)^k),k=1..100),x=0,32): seq(coeff(a,x,n),n=0..31); # Paolo P. Lava, Apr 03 2019
  • Mathematica
    nmax = 31; CoefficientList[Series[1/(1 + x) Product[1/(1 - k x^k/(1 + x)^k), {k, 1, nmax}], {x, 0, nmax}], x]
    Table[Sum[(-1)^(n - k) Binomial[n, k] Total[Times @@@ IntegerPartitions[k]], {k, 0, n}], {n, 0, 31}]

Formula

a(n) = Sum_{k=0..n} (-1)^(n-k)*binomial(n,k)*A006906(k).
Showing 1-4 of 4 results.