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 1-6 of 6 results.

A246585 Zeroth trisection of A246584.

Original entry on oeis.org

1, 12, 92, 470, 2020, 7456, 24962, 76736, 221156, 602200, 1565088, 3902344, 9389022, 21876192, 49542464, 109333520, 235717092, 497416856, 1029271544, 2091480776, 4179123296, 8220922592, 15937506968, 30477650240, 57540075230, 107327212780, 197923648864
Offset: 0

Views

Author

N. J. A. Sloane, Sep 03 2014

Keywords

Crossrefs

Formula

a(n) ~ exp(3*Pi*sqrt(n/2)) / (2^(19/4)*sqrt(3)*n^(5/4)). - Vaclav Kotesovec, Aug 16 2019

A246586 First trisection of A246584.

Original entry on oeis.org

2, 26, 160, 784, 3152, 11290, 36556, 110012, 310482, 832224, 2131072, 5249356, 12488368, 28816368, 64676460, 141598304, 303031202, 635197072, 1306210848, 2639071792, 5245173264, 10266881562, 19811351308, 37720810240, 70922550372, 131777935396, 242124952896
Offset: 0

Views

Author

N. J. A. Sloane, Sep 03 2014

Keywords

Crossrefs

Formula

a(n) ~ exp(3*Pi*sqrt(n/2)) / (2^(19/4)*sqrt(3)*n^(5/4)). - Vaclav Kotesovec, Aug 16 2019

A246587 Second trisection of A246584.

Original entry on oeis.org

6, 48, 282, 1260, 4896, 16836, 53232, 156384, 433776, 1143696, 2890266, 7032576, 16557084, 37838052, 84206724, 182913216, 388685430, 809399280, 1654446816, 3323927340, 6572070528, 12801615744, 24590359284, 46619988384, 87302773392, 161597518272, 295849759728
Offset: 0

Views

Author

N. J. A. Sloane, Sep 03 2014

Keywords

Crossrefs

Formula

a(n) ~ exp(3*Pi*sqrt(n/2)) / (2^(19/4)*sqrt(3)*n^(5/4)). - Vaclav Kotesovec, Aug 16 2019
a(n) = A246584(3*n+2). - Alois P. Heinz, Oct 27 2022

A327048 Expansion of Product_{k>=1} (1 + x^k) * (1 + x^(2*k)) * (1 + x^(3*k)) / ((1 - x^k) * (1 - x^(2*k)) * (1 - x^(3*k))).

Original entry on oeis.org

1, 2, 6, 14, 30, 60, 120, 220, 402, 710, 1224, 2064, 3438, 5596, 9012, 14304, 22422, 34740, 53330, 80960, 121908, 181976, 269484, 396072, 578232, 838258, 1207896, 1730058, 2463900, 3490020, 4918572, 6897012, 9626610, 13375776, 18504852, 25494456, 34985530
Offset: 0

Views

Author

Vaclav Kotesovec, Aug 16 2019

Keywords

Comments

Convolution of A327045 and A327042.

Crossrefs

Programs

  • Mathematica
    nmax = 50; CoefficientList[Series[Product[(1+x^k) * (1+x^(2*k)) * (1+x^(3*k)) / ((1-x^k) * (1-x^(2*k)) * (1-x^(3*k))), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) ~ 11 * exp(sqrt(11*n/6)*Pi) / (2^(13/2)*sqrt(3)*n^(3/2)).

A327049 Expansion of Product_{k>=1} (1 + x^k) * (1 + x^(2*k)) * (1 + x^(3*k)) * (1 + x^(4*k)) / ((1 - x^k) * (1 - x^(2*k)) * (1 - x^(3*k)) * (1 - x^(4*k))).

Original entry on oeis.org

1, 2, 6, 14, 32, 64, 132, 248, 466, 838, 1488, 2560, 4370, 7272, 11988, 19424, 31160, 49280, 77294, 119780, 184164, 280408, 423808, 635136, 945628, 1397398, 2052536, 2995210, 4346416, 6270272, 8999668, 12848584, 18257122, 25817760, 36349600, 50952064, 71131448
Offset: 0

Views

Author

Vaclav Kotesovec, Aug 16 2019

Keywords

Comments

Convolution of A327046 and A327043.

Crossrefs

Programs

  • Mathematica
    nmax = 50; CoefficientList[Series[Product[(1+x^k) * (1+x^(2*k)) * (1+x^(3*k)) * (1+x^(4*k))/((1-x^k) * (1-x^(2*k)) * (1-x^(3*k)) * (1-x^(4*k))), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) ~ 5^(5/2) * exp(5*Pi*sqrt(n/3)/2) / (2^(17/2)*3^(3/4)*n^(7/4)).

A327050 Expansion of Product_{k>=1} (1 + x^k) * (1 + x^(2*k)) * (1 + x^(3*k)) * (1 + x^(4*k)) * (1 + x^(5*k)) / ((1 - x^k) * (1 - x^(2*k)) * (1 - x^(3*k)) * (1 - x^(4*k)) * (1 - x^(5*k))).

Original entry on oeis.org

1, 2, 6, 14, 32, 66, 136, 260, 494, 902, 1620, 2832, 4890, 8260, 13792, 22664, 36824, 59060, 93814, 147364, 229490, 354052, 541916, 822736, 1240292, 1856246, 2760368, 4078522, 5990900, 8749052, 12708920, 18363656, 26404386, 37783040, 53820120, 76324576
Offset: 0

Views

Author

Vaclav Kotesovec, Aug 16 2019

Keywords

Comments

Convolution of A327047 and A327044.
In general, for fixed m>=1, if g.f. = Product_{k>=1} (Product_{j=1..m} (1 + x^(j*k)) / (1 - x^(j*k))), then a(n) ~ sqrt(Gamma(m+1)) * HarmonicNumber(m)^((m+1)/4) * exp(Pi*sqrt(HarmonicNumber(m)*n)) / (2^(3*(m+1)/2) * n^((m+3)/4)).

Crossrefs

Programs

  • Mathematica
    nmax = 50; CoefficientList[Series[Product[(1+x^k) * (1+x^(2*k)) * (1+x^(3*k)) * (1+x^(4*k)) * (1+x^(5*k)) / ((1-x^k) * (1-x^(2*k)) * (1-x^(3*k)) * (1-x^(4*k)) * (1-x^(5*k))), {k, 1, nmax}], {x, 0, nmax}], x]
    With[{nn=50,xk=x^(k Range[5])},CoefficientList[Series[Product[Times@@(1+xk)/Times@@(1-xk),{k,nn}],{x,0,nn}],x]] (* Harvey P. Dale, Jul 23 2023 *)

Formula

a(n) ~ 137^(3/2) * exp(sqrt(137*n/15)*Pi/2) / (15*2^(21/2)*n^2).
Showing 1-6 of 6 results.