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 1-5 of 5 results.

A263031 Decimal expansion of a constant related to A262877 and A262947 (negated).

Original entry on oeis.org

0, 1, 4, 5, 3, 7, 4, 2, 9, 1, 8, 3, 2, 8, 4, 0, 3, 3, 6, 0, 5, 0, 2, 0, 2, 9, 4, 5, 0, 2, 2, 6, 2, 0, 9, 0, 3, 6, 0, 5, 4, 1, 4, 9, 7, 5, 9, 3, 4, 6, 4, 4, 4, 1, 3, 8, 1, 5, 2, 2, 4, 7, 4, 0, 5, 5, 3, 4, 6, 9, 2, 7, 4, 4, 9, 5, 5, 0, 0, 8, 3, 1, 2, 5, 9, 0, 7, 2, 3, 8, 9, 0, 1, 2, 7, 7, 0, 9, 8, 8, 3, 6, 0, 5, 4, 4
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 08 2015

Keywords

Examples

			-0.01453742918328403360502029450226209036054149759346444138152247405534...

Crossrefs

Cf. A262876, A262877, A262946, A262947, A263030, A075700, A084448, A263405, A263414.

Programs

  • Mathematica
    NIntegrate[1/x*(Exp[-x]/(1 - Exp[-3*x])^2 - 1/(9*x^2) - 2/(9*x) - 5*Exp[-x]/36), {x, 0, Infinity}, WorkingPrecision -> 120, MaxRecursion -> 100, PrecisionGoal -> 110]

Formula

Integral_{x=0..infinity} 1/x*(exp(-x)/(1 - exp(-3*x))^2 - 1/(9*x^2) - 2/(9*x) - 5*exp(-x)/36) dx.
exp(3*(A263030+A263031)) = A^2 * Gamma(1/3) / (3^(11/12) * exp(1/6) * sqrt(2*Pi)), where A = A074962 is the Glaisher-Kinkelin constant.

A263416 a(n) = Product_{k=0..n} (3*k+1)^(n-k).

Original entry on oeis.org

1, 1, 4, 112, 31360, 114150400, 6648119296000, 7356542888181760000, 179090034163620983603200000, 108995627512253039588776345600000000, 1857397104331364341705287836001894400000000000, 981210407605679794692064339146706741991833600000000000000
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 17 2015

Keywords

Links

Crossrefs

Cf. A057863, A074962, A252798, A261024, A263405, A263414, A263417, A369468.

Programs

  • Maple
    A263416:=n->mul((3*k+1)^(n-k), k=0..n): seq(A263416(n), n=0..11); # Wesley Ivan Hurt, Nov 12 2015
  • Mathematica
    Table[Product[(3*k+1)^(n-k),{k,0,n}],{n,0,12}] (* or *)
Table[1/FullSimplify[(Gamma[1/3]^((v-1)/3) / 3^((v-1)/18)) * Exp[Integrate[(E^((3-v)*x) - E^(2*x))/(x*(E^(3*x)-1)^2) + (v-1) * (1/(3*x*(E^(3*x)-1)) + 1/(6*x*E^(3*x)) - (v+1)/(18*x*E^x)), {x, 0, Infinity}]]], {v, 1, 34, 3}]
Round@Table[3^(n(n+1)/2) BarnesG[n+4/3]/(BarnesG[1/3] Gamma[1/3]^(n+1)), {n, 0, 12}] (* Vladimir Reshetnikov, Nov 11 2015 *)
  • PARI
    a(n) = prod(k=0, n, (3*k+1)^(n-k)); \\ Michel Marcus, Nov 12 2015

Formula

a(n) ~ A^(1/3) * 2^(n/2 + 1/6) * 3^(n^2/2 + n/2 - 1/72) * n^(n^2/2 + n/3 - 1/36) * Pi^(n/2 + 1/6) / (Gamma(1/3)^(n + 1/3) * exp(3*n^2/4 + n/3 + Pi/(18*sqrt(3)) - PolyGamma(1, 1/3) / (12*sqrt(3)*Pi) + 1/36)), where A = A074962 is the Glaisher-Kinkelin constant and PolyGamma(1, 1/3) = 10.09559712542709408179200409989... (PolyGamma[1, 1/3] in Mathematica or Psi(1, 1/3) in Maple).
PolyGamma(1, 1/3) = 3^(3/2) * A261024 + 2*Pi^2/3.
From Vladimir Reshetnikov, Nov 11 2015: (Start)
a(n) = 3^(n*(n+1)/2) * G(n+4/3) / (G(1/3) * Gamma(1/3)^(n+1)), where G(x) is the Barnes G-function.
a(n) ~ 3^(n*(n+1)/2) * exp(-(9*n^2+4*n-1)/12) * n^((18*n^2+12*n-1)/36) * (2*Pi)^((3*n+1)/6) / (A * G(1/3) * Gamma(1/3)^(n+1)).
Note that G(1/3) = 3^(1/72) * exp(1/9 + Pi/(18*sqrt(3)) - PolyGamma(1, 1/3)/(12*sqrt(3)*Pi)) / (A^(4/3) * Gamma(1/3)^(2/3)).
(End)

A263405 Expansion of Product_{k>=1} 1/(1-x^(3*k+1))^k.

Original entry on oeis.org

1, 0, 0, 0, 1, 0, 0, 2, 1, 0, 3, 2, 1, 4, 6, 2, 6, 10, 6, 8, 20, 14, 13, 30, 29, 22, 50, 54, 43, 74, 99, 76, 119, 166, 144, 182, 276, 254, 294, 442, 451, 468, 701, 758, 772, 1088, 1270, 1256, 1698, 2052, 2067, 2618, 3294, 3352, 4065, 5162, 5430, 6284, 8050
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 17 2015

Keywords

Links

Crossrefs

Cf. A262876, A263031, A263406, A263414, A263415.

Programs

  • Maple
    with(numtheory):
a:= proc(n) option remember; `if`(n=0, 1, add(add(d*
      `if`(irem(d-1, 3)=0, (d-1)/3, 0),
       d=divisors(j))*a(n-j), j=1..n)/n)
    end:
seq(a(n), n=0..60);  # after Alois P. Heinz, Oct 17 2015
  • Mathematica
    nmax = 60; CoefficientList[Series[Product[1/(1-x^(3*k+1))^k,{k,1,nmax}],{x,0,nmax}],x]
nmax = 60; CoefficientList[Series[E^Sum[x^(4*k)/(k*(1-x^(3*k))^2), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: exp(Sum_{k>=1} x^(4*k)/(k*(1-x^(3*k))^2)).
a(n) ~ c * Zeta(3)^(19/108) * exp(-Pi^4/(3888*Zeta(3)) - Pi^2 * n^(1/3) / (2^(4/3) * 3^(7/3) * Zeta(3)^(1/3)) + 3^(1/3) * Zeta(3)^(1/3) * n^(2/3) / 2^(2/3)) / (2^(35/108) * 3^(23/27) * sqrt(Pi) * n^(73/108)), where c = 3^(1/6) * sqrt(2*Pi) * exp(A263031) / Gamma(1/3) = 1.107474840397395849254161220076423560365022...

A263406 Expansion of Product_{k>=1} 1/(1-x^(3*k+2))^k.

Original entry on oeis.org

1, 0, 0, 0, 0, 1, 0, 0, 2, 0, 1, 3, 0, 2, 4, 1, 6, 5, 2, 10, 7, 6, 19, 9, 14, 29, 14, 28, 46, 23, 53, 66, 43, 95, 99, 76, 158, 143, 141, 256, 217, 247, 403, 326, 432, 617, 509, 720, 935, 801, 1187, 1399, 1281, 1892, 2087, 2047, 2983, 3107, 3272, 4589, 4647
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 17 2015

Keywords

Links

Crossrefs

Cf. A262877, A263030, A263405, A263414, A263415.

Programs

  • Maple
    with(numtheory):
a:= proc(n) option remember; `if`(n=0, 1, add(add(d*
      `if`(irem(d-2, 3)=0, (d-2)/3, 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^(3*k+2))^k,{k,1,nmax}],{x,0,nmax}],x]
nmax = 60; CoefficientList[Series[E^Sum[x^(5*k)/(k*(1-x^(3*k))^2), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: exp(Sum_{k>=1} x^(5*k)/(k*(1-x^(3*k))^2)).
a(n) ~ c * Zeta(3)^(13/108) * exp(-Pi^4/(972*Zeta(3)) - Pi^2 * n^(1/3) / (2^(1/3) * 3^(7/3) * Zeta(3)^(1/3)) + 3^(1/3) * Zeta(3)^(1/3) * n^(2/3) / 2^(2/3)) / (2^(41/108) * 3^(20/27) * sqrt(Pi) * n^(67/108)), where c = 3^(1/3) * Gamma(1/3) * exp(A263030) / sqrt(2*Pi) = 1.2763162741536982965216627321306598385267089489...

A263415 Expansion of Product_{k>=1} 1/(1-x^(3*k+5))^k.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 2, 0, 0, 3, 0, 1, 4, 0, 2, 5, 0, 6, 6, 1, 10, 7, 2, 19, 8, 6, 28, 10, 14, 44, 12, 28, 60, 17, 52, 86, 26, 93, 112, 46, 152, 152, 78, 243, 196, 142, 372, 264, 244, 552, 350, 422, 798, 486, 692, 1136, 680, 1125, 1582, 997, 1758
Offset: 0

Views

Author

Vaclav Kotesovec, Oct 17 2015

Keywords

Comments

In general, if v>0, GCD(v,3)=1 and g.f. = Product_{k>=1} 1/(1-x^(3*k+v))^k, then
a(n) ~ d3(v) * 3^(v^2/27 - 8/9) * exp(-Pi^4 * v^2 / (3888*Zeta(3)) - v * Pi^2 * n^(1/3) / (2^(4/3) * 3^(7/3) * Zeta(3)^(1/3)) + 3^(1/3) * Zeta(3)^(1/3) * n^(2/3) / 2^(2/3)) * n^(v^2/54 - 25/36) / (sqrt(Pi) * 2^(v^2/54 + 11/36) * Zeta(3)^(v^2/54 - 7/36)), where
d3(v) = exp(Integral_{x=0..infinity} (exp((3-v)*x) / (exp(3*x)-1)^2 + (1/12 - v^2/18)/exp(x) - 1/(9*x^2) + v/(9*x))/x dx).
if mod(v,3)=1, then d3(v) = exp(A263031) * 2^((v+2)/6) * 3^((v+2)/18) * Pi^((v+2)/6) / (Gamma(1/3)^((v+2)/3) * A263416((v-1)/3)).
if mod(v,3)=2, then d3(v) = exp(A263030) * 2^((v+1)/6) * Pi^((v+1)/6) / (3^((v+1)/18) * Gamma(2/3)^((v+1)/3) * A263417((v-2)/3)).

Links

Crossrefs

Cf. A262877, A262876, A263405 (v=1), A263406 (v=2), A263414 (v=4), A263030, A263417.

Programs

  • Maple
    with(numtheory):
a:= proc(n) option remember; local r; `if`(n=0, 1,
       add(add(`if`(irem(d-3, 3, 'r')=2, d*r, 0)
        , d=divisors(j))*a(n-j), j=1..n)/n)
    end:
seq(a(n), n=0..70);  # Alois P. Heinz, Oct 17 2015
  • Mathematica
    nmax = 80; CoefficientList[Series[Product[1/(1-x^(3*k+5))^k,{k,1,nmax}],{x,0,nmax}],x]
nmax = 80; CoefficientList[Series[E^Sum[x^(8*k)/(k*(1-x^(3*k))^2), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: exp(Sum_{k>=1} x^(8*k)/(k*(1-x^(3*k))^2)).
a(n) ~ c * 3^(1/27) * exp(-25*Pi^4 / (3888*Zeta(3)) - 5*Pi^2 * n^(1/3) / (2^(4/3) * 3^(7/3) * Zeta(3)^(1/3)) + 3^(1/3) * Zeta(3)^(1/3) * n^(2/3) / 2^(2/3)) / (sqrt(Pi) * 2^(83/108) * Zeta(3)^(29/108) * n^(25/108)), where c = exp(A263030) * Pi / (3^(1/3) * Gamma(2/3)^2) = 0.98365214791227284535715328899346961376609...
Showing 1-5 of 5 results.

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