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 1-9 of 9 results.

A035528 Euler transform of A027656(n-1).

Original entry on oeis.org

0, 1, 1, 3, 3, 6, 9, 13, 19, 28, 42, 57, 84, 115, 164, 227, 313, 429, 588, 799, 1079, 1461, 1952, 2617, 3480, 4627, 6111, 8072, 10604, 13905, 18181, 23701, 30828, 39990, 51763, 66822, 86124, 110687, 142039, 181841, 232409, 296401, 377419, 479635, 608558, 770818
Offset: 0

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Author

Keywords

Comments

Also the weigh transform of A003602. - John Keith, Nov 17 2021

Crossrefs

Programs

  • Mathematica
    nmax = 50; CoefficientList[Series[-1 + Product[1/(1 - x^(2*k-1))^k, {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Aug 19 2015 *)
    nmax = 100; Flatten[{0, Rest[CoefficientList[Series[E^Sum[1/j*x^j/(1 - x^(2*j))^2, {j, 1, nmax}], {x, 0, nmax}], x]]}] (* Vaclav Kotesovec, Oct 10 2015 *)

Formula

a(n) ~ A^(1/2) * Zeta(3)^(11/72) * exp(-1/24 - Pi^4/(1728*Zeta(3)) + Pi^2 * n^(1/3)/(3*2^(8/3)*Zeta(3)^(1/3)) + 3*Zeta(3)^(1/3) * n^(2/3)/2^(4/3)) / (sqrt(3*Pi) * 2^(71/72) * n^(47/72)), where Zeta(3) = A002117 and A = A074962 is the Glaisher-Kinkelin constant. - Vaclav Kotesovec, Oct 02 2015

A263140 Expansion of Product_{k>=1} (1 + x^(2*k-1))^k.

Original entry on oeis.org

1, 1, 0, 2, 2, 3, 4, 5, 10, 11, 16, 20, 31, 39, 50, 71, 93, 124, 154, 211, 271, 357, 449, 587, 762, 968, 1233, 1571, 2021, 2535, 3220, 4049, 5145, 6431, 8070, 10105, 12670, 15784, 19619, 24447, 30348, 37635, 46464, 57532, 70945, 87477, 107456, 132192, 162220
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 10 2015

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 100; CoefficientList[Series[Product[(1 + x^(2*k-1))^k, {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 100; CoefficientList[Series[E^Sum[(-1)^(j+1)/j*x^j/(1 - x^(2*j))^2, {j, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: exp(Sum_{j>=1} (-1)^(j+1)/j*x^j/(1 - x^(2*j))^2).
a(n) ~ exp(-Pi^4 / (5184*Zeta(3)) + Pi^2 * n^(1/3) / (8 * 3^(4/3) * Zeta(3)^(1/3)) + 3^(4/3) * Zeta(3)^(1/3) * n^(2/3)/4) * Zeta(3)^(1/6) / (2^(23/24) * 3^(1/3)* sqrt(Pi) * n^(2/3)).

A263352 Expansion of Product_{k>=1} 1/(1 - x^(2*k+3))^k.

Original entry on oeis.org

1, 0, 0, 0, 0, 1, 0, 2, 0, 3, 1, 4, 2, 5, 6, 7, 10, 9, 19, 14, 29, 23, 46, 38, 66, 64, 99, 107, 143, 171, 211, 270, 311, 418, 465, 633, 698, 945, 1049, 1399, 1579, 2052, 2364, 2997, 3527, 4366, 5219, 6339, 7686, 9197, 11234, 13321, 16340, 19261, 23622, 27796
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 16 2015

Keywords

Comments

From Vaclav Kotesovec, Oct 17 2015: (Start)
In general, if g.f. = Product_{k>=1} 1/(1-x^(2*k+v))^k and v>0 is odd, then a(n) ~ d2(v) * (2*n)^(v^2/24 - 25/36) * exp(-Pi^4 * v^2 / (1728*Zeta(3)) - Pi^2 * v * n^(1/3) /(3 * 2^(8/3) * Zeta(3)^(1/3)) + 3*Zeta(3)^(1/3) * n^(2/3) / 2^(4/3)) / (sqrt(3*Pi) * Zeta(3)^(v^2/24 - 7/36)), where Zeta(3) = A002117.
d2(v) = exp(Integral_{x=0..infinity} 1/(x*exp((v-2)*x) * (exp(2*x)- 1)^2) - (3*v^2-2)/(24*x*exp(x)) + v/(4*x^2) - 1/(4*x^3) dx).
d2(v) = 2^(v/4 - 1/12) * exp(-Zeta'(-1)/2) / Product_{j=1..(v-1)/2} (2*j-1)!!, where Zeta'(-1) = A084448 and Product_{j=1..(v-1)/2} (2*j-1)!! = A057863((v-1)/2).
d2(v) = 2^(1/12 + v/4 - v^2/8) * exp(1/12) * Pi^(v/4) / (A * G(v/2 + 1)), where A = A074962 is the Glaisher-Kinkelin constant and G is the Barnes G-function.
(End)

Crossrefs

Programs

  • Maple
    with(numtheory):
    a:= proc(n) option remember; `if`(n=0, 1, add(add(d*
          `if`(d>1 and d::odd, (d-3)/2, 0),
          d=divisors(j))*a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..60);  # Alois P. Heinz, Oct 17 2015
  • Mathematica
    nmax = 60; CoefficientList[Series[Product[1/(1 - x^(2*k+3))^k, {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) ~ 2^(25/72) * sqrt(A) * exp(-1/24 + 3 * 2^(-4/3) * Zeta(3)^(1/3) * n^(2/3) - Pi^4/(192*Zeta(3)) - Pi^2 * n^(1/3)/(2^(8/3) * Zeta(3)^(1/3))) / (sqrt(3*Pi) * Zeta(3)^(13/72) * n^(23/72)), where Zeta(3) = A002117 and A = A074962 is the Glaisher-Kinkelin constant.

A263149 Expansion of Product_{k>=1} (1 + x^(2*k+1))^k.

Original entry on oeis.org

1, 0, 0, 1, 0, 2, 0, 3, 2, 4, 4, 5, 10, 7, 16, 13, 28, 22, 40, 41, 63, 73, 90, 123, 143, 199, 214, 316, 343, 483, 532, 733, 848, 1099, 1305, 1644, 2029, 2448, 3067, 3657, 4643, 5443, 6892, 8107, 10224, 12031, 14974, 17798, 21941, 26190, 31867, 38381, 46300
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 10 2015

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 100; CoefficientList[Series[Product[(1 + x^(2*k+1))^k, {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 100; CoefficientList[Series[E^Sum[(-1)^(j+1)/j*x^(3*j)/(1 - x^(2*j))^2, {j, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: exp(Sum_{j>=1} (-1)^(j+1)/j*x^(3*j)/(1 - x^(2*j))^2).
a(n) ~ exp(-Pi^4/(5184*Zeta(3)) - Pi^2 * n^(1/3) / (8 * 3^(4/3) * Zeta(3)^(1/3)) + 3^(4/3) * Zeta(3)^(1/3) * n^(2/3)/4) * Zeta(3)^(1/6) / (2^(23/24) * 3^(1/3)* sqrt(Pi) * n^(2/3)).

A263395 Expansion of Product_{k>=1} 1/(1 - x^(2*k+5))^k.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 1, 0, 2, 0, 3, 0, 4, 1, 5, 2, 6, 6, 7, 10, 9, 19, 11, 28, 16, 44, 25, 61, 40, 87, 65, 116, 107, 160, 168, 215, 260, 295, 393, 407, 578, 573, 836, 814, 1193, 1167, 1675, 1684, 2335, 2427, 3238, 3501, 4468, 5014, 6161, 7152, 8494, 10121
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 16 2015

Keywords

Crossrefs

Programs

  • Maple
    with(numtheory):
    a:= proc(n) option remember; local r; `if`(n=0, 1,
           add(add(`if`(irem(d-4, 2, 'r')=1, d*r, 0)
           , d=divisors(j))*a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..60);  # Alois P. Heinz, Oct 17 2015
  • Mathematica
    nmax = 60; CoefficientList[Series[Product[1/(1 - x^(2*k+5))^k, {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 60; CoefficientList[Series[E^Sum[x^(7*k)/(k*(1-x^(2*k))^2), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: exp(Sum_{k>=1} x^(7*k)/(k*(1-x^(2*k))^2)).
a(n) ~ 2^(109/72) * exp(-1/24 - 25*Pi^4/(1728*Zeta(3)) - 5*Pi^2 * n^(1/3) / (12 * 2^(2/3) * Zeta(3)^(1/3)) + 3 * Zeta(3)^(1/3) * n^(2/3) / 2^(4/3)) * sqrt(A) * n^(25/72) / (3*sqrt(3*Pi) * Zeta(3)^(61/72)), where Zeta(3) = A002117 and A = A074962 is the Glaisher-Kinkelin constant.

A263396 Expansion of Product_{k>=1} 1/(1 - x^(2*k+7))^k.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 2, 0, 3, 0, 4, 0, 5, 1, 6, 2, 7, 6, 8, 10, 9, 19, 11, 28, 13, 44, 18, 60, 27, 85, 42, 111, 67, 148, 109, 188, 169, 245, 260, 313, 390, 408, 568, 535, 811, 717, 1139, 974, 1568, 1343, 2134, 1872, 2873, 2621, 3832, 3687, 5088
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 16 2015

Keywords

Crossrefs

Programs

  • Maple
    with(numtheory):
    a:= proc(n) option remember; local r; `if`(n=0, 1,
           add(add(`if`(irem(d-6, 2, 'r')=1, d*r, 0)
           , d=divisors(j))*a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..65);  # Alois P. Heinz, Oct 17 2015
  • Mathematica
    nmax = 60; CoefficientList[Series[Product[1/(1 - x^(2*k+7))^k, {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 60; CoefficientList[Series[E^Sum[x^(9*k)/(k*(1-x^(2*k))^2), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: exp(Sum_{k>=1} x^(9*k)/(k*(1-x^(2*k))^2)).
a(n) ~ 8 * 2^(1/72) * exp(-1/24 - 49*Pi^4/(1728*Zeta(3)) - 7*Pi^2 * n^(1/3) / (12 * 2^(2/3) * Zeta(3)^(1/3)) + 3 * Zeta(3)^(1/3) * n^(2/3) / 2^(4/3)) * sqrt(A) * n^(97/72) / (45*sqrt(3*Pi) * Zeta(3)^(133/72)), where Zeta(3) = A002117 and A = A074962 is the Glaisher-Kinkelin constant.

A263397 Expansion of Product_{k>=1} 1/(1 - x^(2*k+9))^k.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 2, 0, 3, 0, 4, 0, 5, 0, 6, 1, 7, 2, 8, 6, 9, 10, 10, 19, 11, 28, 13, 44, 15, 60, 20, 85, 29, 110, 44, 146, 69, 183, 111, 233, 171, 286, 262, 358, 391, 441, 568, 553, 808, 697, 1129, 898, 1543, 1174, 2080, 1563, 2766
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 16 2015

Keywords

Comments

In general, if g.f. = Product_{k>=1} 1/(1-x^(2*k+v))^k and v>0 is odd, then a(n) ~ d2(v) * (2*n)^(v^2/24 - 25/36) * exp(-Pi^4 * v^2 / (1728*Zeta(3)) - Pi^2 * v * n^(1/3) /(3 * 2^(8/3) * Zeta(3)^(1/3)) + 3*Zeta(3)^(1/3) * n^(2/3) / 2^(4/3)) / (sqrt(3*Pi) * Zeta(3)^(v^2/24 - 7/36)), where Zeta(3) = A002117.
d2(v) = exp(Integral_{x=0..infinity} 1/(x*exp((v-2)*x) * (exp(2*x)- 1)^2) - (3*v^2-2)/(24*x*exp(x)) + v/(4*x^2) - 1/(4*x^3) dx).
d2(v) = 2^(v/4 - 1/12) * exp(-Zeta'(-1)/2) / Product_{j=1..(v-1)/2} (2*j-1)!!, where Zeta'(-1) = A084448 and Product_{j=1..(v-1)/2} (2*j-1)!! = A057863((v-1)/2).
d2(v) = 2^(1/12 + v/4 - v^2/8) * exp(1/12) * Pi^(v/4) / (A * G(v/2 + 1)), where A = A074962 is the Glaisher-Kinkelin constant and G is the Barnes G-function.

Crossrefs

Cf. A035528 (v=-1), A263150 (v=1), A263352 (v=3), A263395 (v=5), A263396 (v=7).

Programs

  • Maple
    with(numtheory):
    a:= proc(n) option remember; local r; `if`(n=0, 1,
           add(add(`if`(irem(d-8, 2, 'r')=1, d*r, 0)
           , d=divisors(j))*a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..65);  # Alois P. Heinz, Oct 17 2015
  • Mathematica
    nmax = 60; CoefficientList[Series[Product[1/(1 - x^(2*k+9))^k, {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 60; CoefficientList[Series[E^Sum[x^(11*k)/(k*(1-x^(2*k))^2), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: exp(Sum_{k>=1} x^(11*k)/(k*(1-x^(2*k))^2)).
a(n) ~ 16 * 2^(61/72) * exp(-1/24 - 3*Pi^4/(64*Zeta(3)) - 3*Pi^2 * n^(1/3) / (2^(8/3) * Zeta(3)^(1/3)) + 3 * Zeta(3)^(1/3) * n^(2/3) / 2^(4/3)) * sqrt(A) * n^(193/72) / (4725*sqrt(3*Pi) * Zeta(3)^(229/72)), where Zeta(3) = A002117 and A = A074962 is the Glaisher-Kinkelin constant.

A263199 Expansion of Product_{k>=1} 1/(1 - x^(2*k+1))^(2*k+1).

Original entry on oeis.org

1, 0, 0, 3, 0, 5, 6, 7, 15, 19, 36, 41, 77, 100, 156, 230, 317, 482, 665, 981, 1354, 1967, 2710, 3852, 5363, 7453, 10373, 14287, 19780, 27022, 37220, 50583, 69140, 93693, 127098, 171640, 231469, 311323, 417627, 559577, 747122, 996947, 1325872, 1761900
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 12 2015

Keywords

Crossrefs

Programs

  • Maple
    with(numtheory):
    b:= proc(n) option remember; `if`(n=0, 1, add(add(d*
          `if`(d::even, 0, d), d=divisors(j))*b(n-j), j=1..n)/n)
        end:
    seq(b(n)-b(n-1), n=0..60);  # after Alois P. Heinz
  • Mathematica
    nmax = 100; CoefficientList[Series[Product[1/(1 - x^(2*k+1))^(2*k+1),{k,1,nmax}],{x,0,nmax}],x]

Formula

For n>1, a(n) = A262811(n) - A262811(n-1).
a(n) ~ A * Zeta(3)^(17/36) * exp(-1/12 + 3 * Zeta(3)^(1/3) * n^(2/3)/2) / (2^(2/3) * sqrt(3*Pi) * n^(35/36)), where Zeta(3) = A002117 and A = A074962 is the Glaisher-Kinkelin constant.

A361008 G.f.: Product_{k >= 0} ((1 + x^(2*k+1)) / (1 - x^(2*k+1)))^k.

Original entry on oeis.org

1, 0, 0, 2, 0, 4, 2, 6, 8, 10, 20, 18, 42, 40, 78, 92, 140, 192, 258, 382, 480, 728, 902, 1334, 1698, 2404, 3148, 4292, 5742, 7608, 10304, 13430, 18192, 23592, 31720, 41144, 54766, 71188, 93762, 122156, 159420, 207820, 269380, 350726, 452434, 587520, 755446
Offset: 0

Views

Author

Vaclav Kotesovec, Apr 20 2023

Keywords

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[Product[((1 + x^(2*k + 1))/(1 - x^(2*k + 1)))^k, {k, 0, n}], {x, 0, n}], {n, 0, 50}]

Formula

a(n) ~ sqrt(A/(3*Pi)) * (7*zeta(3))^(11/72) * exp(3*(7*zeta(3))^(1/3) * n^(2/3)/4 - Pi^2 * n^(1/3)/(8*(7*zeta(3))^(1/3)) - 1/24 - Pi^4/(1344*zeta(3))) / (2^(3/4) * n^(47/72)), where A = A074962 is the Glaisher-Kinkelin constant.
Showing 1-9 of 9 results.