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.

A262878 Expansion of Product_{k>=1} (1+x^(3*k-1))^k.

Original entry on oeis.org

1, 0, 1, 0, 0, 2, 0, 2, 3, 0, 4, 4, 1, 10, 5, 6, 16, 6, 14, 28, 10, 32, 40, 18, 63, 60, 42, 112, 83, 84, 187, 124, 172, 300, 186, 320, 456, 302, 581, 684, 507, 982, 1004, 874, 1624, 1476, 1508, 2566, 2174, 2582, 3981, 3262, 4338, 6002, 4945, 7138, 8947, 7660
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 04 2015

Keywords

Comments

In general, if s>0, t>0, GCD(s,t)=1 and g.f. = Product_{k>=1} (1 + x^(s*k-t))^k then a(n) ~ 2^(t^2/(2*s^2) - 3/4) * s^(2/3) * Zeta(3)^(1/6) * exp(-Pi^4 * t^2 / (1296 * s^2 * Zeta(3)) + Pi^2 * t * 2^(1/3) * 3^(2/3) * s^(2/3) * n^(1/3) / (36 * s^2 * Zeta(3)^(1/3)) + 3^(4/3) * Zeta(3)^(1/3) * n^(2/3) / (2^(4/3) * s^(2/3)) ) / (3^(1/3) * s * sqrt(Pi) * n^(2/3)). - Vaclav Kotesovec, Oct 12 2015

Crossrefs

Programs

  • Maple
    with(numtheory):
    b:= n-> `if`(n<3, n-1, (p-> [0, -r, 2*r, 0, 0, 2*r+1][p]
             )(1+irem(n+3, 6, 'r'))):
    a:= proc(n) option remember; `if`(n=0, 1, add(add(
          d*b(d), d=divisors(j))*a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..60);  # Alois P. Heinz, Oct 05 2015
  • Mathematica
    nmax=100; CoefficientList[Series[Product[(1+x^(3k-1))^k, {k, 1, nmax}], {x, 0, nmax}], x]
    nmax=100; CoefficientList[Series[E^Sum[(-1)^(j+1)/j*x^(2*j)/(1-x^(3j))^2,{j,1,nmax}],{x,0,nmax}],x]

Formula

a(n) ~ exp(2^(-4/3) * 3^(2/3) * Zeta(3)^(1/3) * n^(2/3) + Pi^2 * n^(1/3) / (2^(5/3)*3^(8/3) * Zeta(3)^(1/3)) - Pi^4/(11664*Zeta(3))) * Zeta(3)^(1/6) / (2^(25/36) * 3^(2/3) * sqrt(Pi) * n^(2/3)).

A262879 Expansion of Product_{k>=1} (1+x^(3*k-2))^k.

Original entry on oeis.org

1, 1, 0, 0, 2, 2, 0, 3, 4, 1, 4, 10, 6, 5, 16, 14, 9, 28, 32, 17, 40, 63, 41, 63, 112, 83, 94, 187, 171, 156, 301, 319, 260, 467, 580, 465, 713, 981, 818, 1095, 1627, 1452, 1682, 2584, 2510, 2632, 4047, 4266, 4162, 6181, 7054, 6685, 9396, 11423, 10753, 14132
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 04 2015

Keywords

Crossrefs

Programs

  • Mathematica
    nmax=100; CoefficientList[Series[Product[(1+x^(3k-2))^k, {k, 1, nmax}], {x, 0, nmax}], x]
    nmax=100; CoefficientList[Series[E^Sum[(-1)^(j+1)/j*x^j/(1-x^(3j))^2,{j,1,nmax}],{x,0,nmax}],x]
    Clear[a]; a[n_]:=a[n] = If[n==0, 1, Sum[Sum[d*{0, 2*Floor[d/6] + 1, -Floor[d/6] - 1, 0, 2*Floor[d/6] + 2, 0}[[1 + Mod[d, 6]]], {d, Divisors[j]}] * a[n-j], {j, 1, n}]/n]; Table[a[n], {n, 0, 100}]

Formula

a(n) ~ exp(2^(-4/3) * 3^(2/3) * Zeta(3)^(1/3) * n^(2/3) + Pi^2 * n^(1/3) / (2^(2/3) * 3^(8/3) * Zeta(3)^(1/3)) - Pi^4/(2916*Zeta(3))) * Zeta(3)^(1/6) / (2^(19/36) * 3^(2/3) * sqrt(Pi) * n^(2/3)).

A262924 Expansion of Product_{k>=1} (1 + x^(3*k-1))^(3*k-1) * (1 + x^(3*k-2))^(3*k-2).

Original entry on oeis.org

1, 1, 2, 2, 5, 10, 13, 25, 35, 57, 87, 134, 211, 306, 458, 684, 996, 1465, 2129, 3073, 4411, 6288, 8977, 12707, 17913, 25185, 35231, 49078, 68228, 94490, 130408, 179425, 246121, 336681, 459239, 624842, 847986, 1147728, 1549773, 2087972, 2806455, 3764136
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 04 2015

Keywords

Comments

Convolution of A262948 and A262949.

Crossrefs

Programs

  • Mathematica
    nmax=60; CoefficientList[Series[Product[(1 + x^(3*k-1))^(3*k-1)*(1 + x^(3*k-2))^(3*k-2), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) ~ exp(3*Zeta(3)^(1/3)*n^(2/3)/2) * Zeta(3)^(1/6) / (2^(1/3) * sqrt(3*Pi) * n^(2/3)).

A262883 Expansion of Product_{k>=1} 1/((1-x^(3*k-1))*(1-x^(3*k-2)))^k.

Original entry on oeis.org

1, 1, 2, 2, 5, 7, 10, 15, 24, 33, 49, 68, 100, 136, 193, 267, 370, 501, 690, 928, 1260, 1687, 2265, 3007, 4006, 5289, 6987, 9163, 12033, 15698, 20469, 26572, 34470, 44510, 57442, 73861, 94852, 121439, 155287, 198007, 252165, 320335, 406396, 514410, 650288
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 04 2015

Keywords

Comments

Convolution of A262876 and A262877.

Crossrefs

Programs

  • Maple
    with(numtheory):
    a:= proc(n) option remember; `if`(n=0, 1, add(add(d*
          `if`(irem(d+3, 3, 'r')=0, 0, r), d=divisors(j))*a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..60);  # Alois P. Heinz, Oct 05 2015
  • Mathematica
    nmax = 50; CoefficientList[Series[Product[1/((1-x^(3*k-1))*(1-x^(3*k-2)))^k, {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) ~ exp(-1/18 - Pi^4/(864*Zeta(3)) + (3*Zeta(3)/2)^(1/3) * n^(2/3) + Pi^2 * n^(1/3) / (2^(5/3)*3^(4/3)*Zeta(3)^(1/3))) * A^(2/3) * Gamma(4/3)^(1/3) * Zeta(3)^(7/54) / (2^(11/27) * 3^(79/108) * Pi^(2/3) * n^(17/27)), where Zeta(3) = A002117 and A = A074962 is the Glaisher-Kinkelin constant.

A262949 Expansion of Product_{k>=1} (1 + x^(3*k-2))^(3*k-2).

Original entry on oeis.org

1, 1, 0, 0, 4, 4, 0, 7, 13, 6, 10, 38, 32, 17, 74, 103, 59, 139, 266, 191, 247, 593, 581, 513, 1175, 1487, 1190, 2223, 3453, 2938, 4158, 7264, 7095, 8052, 14430, 16308, 16246, 27364, 35347, 34096, 50997, 72595, 72163, 94707, 142522, 151435, 178047, 270112
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 05 2015

Keywords

Crossrefs

Programs

  • Mathematica
    nmax=60; CoefficientList[Series[Product[(1 + x^(3*k-2))^(3*k-2),{k,1,nmax}],{x,0,nmax}],x]

Formula

a(n) ~ exp(3 * 2^(-4/3) * Zeta(3)^(1/3) * n^(2/3)) * Zeta(3)^(1/6) / (2^(7/12) * sqrt(3*Pi) * n^(2/3)).

A262948 Expansion of Product_{k>=1} (1 + x^(3*k-1))^(3*k-1).

Original entry on oeis.org

1, 0, 2, 0, 1, 5, 0, 10, 8, 5, 26, 11, 28, 62, 24, 101, 111, 77, 260, 202, 268, 583, 382, 761, 1165, 847, 1940, 2198, 2061, 4346, 4084, 5078, 9039, 7844, 11978, 17620, 15721, 26648, 33219, 32894, 56000, 61494, 69653, 111884, 114265, 146557, 214864, 214967
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 05 2015

Keywords

Crossrefs

Programs

  • Mathematica
    nmax=60; CoefficientList[Series[Product[(1 + x^(3*k-1))^(3*k-1),{k,1,nmax}],{x,0,nmax}],x]

Formula

a(n) ~ exp(3 * 2^(-4/3) * Zeta(3)^(1/3) * n^(2/3)) * Zeta(3)^(1/6) / (2^(7/12) * sqrt(3*Pi) * n^(2/3)).
Showing 1-6 of 6 results.