A268506 -id:A268506 - cp's OEIS frontend

A098694 Double-superfactorials: a(n) = Product_{k=1..n} (2k)!.

1, 2, 48, 34560, 1393459200, 5056584744960000, 2422112183371431936000000, 211155601241022491077587763200000000, 4417964278440225627098723475313498521600000000000

Offset: 0

Ralf Stephan, Sep 22 2004

nonn

Hankel transform of double factorial numbers A001147. - Paul Barry, Jan 28 2008

Hankel transform of A112934(n+1). - Paul Barry, Dec 04 2009

Seiichi Manyama, Table of n, a(n) for n = 0..28
C. Radoux, Déterminants de Hankel et théorème de Sylvester, Séminaire Lotharingien de Combinatoire, B28b (1992), 9 pp.

Cf. A000178, A010050, A074962, A168467, A268504, A268505, A268506, A271946, A271947.

[&*[ Factorial(2*k): k in [0..n] ]: n in [0..10]]; // Vincenzo Librandi, Dec 11 2016

Table[Product[(2k)!,{k,1,n}],{n,0,10}] (* Vaclav Kotesovec, Nov 13 2014 *)

a(n) = prod(k=1, n, (2*k)!); \\ Michel Marcus, Dec 11 2016

from math import prod
def A098694(n): return prod(((k+1)*((k<<1)+1)<<1)**(n-k) for k in range(1,n+1))<Chai Wah Wu, Nov 26 2023

a(n) = Product_{k=0..n} (2*(k+1)*(2*k+1))^(n-k). - Paul Barry, Jan 28 2008
a(n) = A000178(n)*A057863(n)*A006125(n+1) = A121835(n)*A006125(n+1). - Paul Barry, Jan 28 2008
G.f.: G(0)/(2*x)-1/x, where G(k)= 1  + 1/(1 - 1/(1 + 1/(2*k+2)!/x/G(k+1))); (continued fraction). - Sergei N. Gladkovskii, Jun 14 2013
a(n) ~ 2^(n^2+2*n+17/24) * n^(n^2+3*n/2+11/24) * Pi^((n+1)/2) / (A^(1/2) * exp(3*n^2/2+3*n/2-1/24)), where A = 1.2824271291... is the Glaisher-Kinkelin constant (see A074962). - Vaclav Kotesovec, Nov 13 2014
a(n) = A^(3/2)*2^(n^2+n-1/24)*Pi^(-n/2-1/4)*G(n+3/2)*G(n+2)/exp(1/8), where G(n) is the Barnes G-function and A is the Glaisher-Kinkelin constant. - Ilya Gutkovskiy, Dec 11 2016
a(n) = A000178(2*n + 1) / A168467(n). - Vaclav Kotesovec, Oct 28 2017
For n > 0, a(n) = 2^((n+1)/2) * n * sqrt(BarnesG(2*n)*Gamma(n)) * Gamma(2*n). - Vaclav Kotesovec, Nov 27 2024

A268504 a(n) = Product_{k=0..n} (3*k)!.

Original entry on oeis.org

1, 6, 4320, 1567641600, 750902834626560000, 981936389699695364014080000000, 6286723722110812136775527266768650240000000000, 321194638135877430211257700556824829511701622266265600000000000000

Offset: 0

Vaclav Kotesovec, Apr 16 2016

nonn

Partial products of A100732. - Michel Marcus, Jul 06 2019

Seiichi Manyama, Table of n, a(n) for n = 0..22

Cf. A000178, A098694, A100732, A268196, A268505, A268506, A271946, A271947.

Mathematica
```
Table[Product[(3*k)!,{k,0,n}],{n,0,10}]
```

{a(n) = prod(k=1, n, (3*k)!)} \\ Seiichi Manyama, Jul 06 2019

a(n) ~ Gamma(1/3)^(1/3) * 3^(3*n^2/2 + 2*n + 11/36) * 2^(n/2 + 1/3) * Pi^(n/2 + 1/3) * n^(3*n^2/2 + 2*n + 19/36) / (A^(1/3) * exp(9*n^2/4 + 2*n - 1/36)), where A = A074962 is the Glaisher-Kinkelin constant.

A100734 a(n) = (5*n)!.

Original entry on oeis.org

1, 120, 3628800, 1307674368000, 2432902008176640000, 15511210043330985984000000, 265252859812191058636308480000000, 10333147966386144929666651337523200000000

Offset: 0

Ralf Stephan, Dec 08 2004

Vincenzo Librandi, Table of n, a(n) for n = 0..90

Cf. A000142, A010050, A100732, A100733, A268506, A269296.

[Factorial(5*n): n in [0..10]]; // Vincenzo Librandi, Sep 24 2011

(5*Range[0,10])! (* Harvey P. Dale, May 06 2015 *)

E.g.f.: 1/(1-x^5).
From Ilya Gutkovskiy, Jan 20 2017: (Start)
a(n) ~ sqrt(2*Pi)*5^(5*n + 1/2)*n^(5*n + 1/2)/exp(5*n).
Sum_{n>=0} 1/a(n) = A269296. (End)

A268505 a(n) = Product_{k=0..n} (4*k)!.

Original entry on oeis.org

1, 24, 967680, 463520268288000, 9698137182219213471744000000, 23594617426193665303453830729600860160000000000, 14639242671589099207353038379393488170313478620292159897600000000000000

Offset: 0

Vaclav Kotesovec, Apr 16 2016

nonn

Partial products of A100733. - Michel Marcus, Jul 06 2019

Seiichi Manyama, Table of n, a(n) for n = 0..19

Cf. A000178, A098694, A100733, A268504, A268506, A271946, A271947.

Mathematica
```
Table[Product[(4*k)!,{k,0,n}],{n,0,8}]
```

{a(n) = prod(k=1, n, (4*k)!)} \\ Seiichi Manyama, Jul 06 2019

a(n) ~ Gamma(1/4)^(1/2) * 2^(5/6 + 11*n/2 + 4*n^2) * exp(1/48 - 5*n/2 - 3*n^2) * n^(29/48 + 5*n/2 + 2*n^2) * Pi^(1/4 + n/2) / A^(1/4), where A = A074962 is the Glaisher-Kinkelin constant.

a(n) = A^(15/4) * sqrt(Gamma(1/4)) * exp(-5/16) * 2^(4*n^2 + 7*n/2 - 5/12) * BarnesG(n + 5/4) * BarnesG(n + 3/2) * BarnesG(n + 7/4) * BarnesG(n+2) / Pi^(3*n/2 + 1). - Vaclav Kotesovec, Apr 23 2024

A271946 a(n) = Product_{k=0..n} (6*k)!.

Original entry on oeis.org

1, 720, 344881152000, 2208058019165981638656000000, 1369986068925795885347091500568179543900160000000000, 363392722685428853076589064611759104109572860599125858715484081356800000000000000000

Offset: 0

Vaclav Kotesovec, Apr 17 2016

nonn

The next term has 126 digits.

Partial products of A195390. - Michel Marcus, Jul 06 2019

Seiichi Manyama, Table of n, a(n) for n = 0..15

Cf. A000178, A098694, A195390, A268504, A268505, A268506, A271947.

Mathematica
```
Table[Product[(6*k)!,{k,0,n}],{n,0,8}]
```

{a(n) = prod(k=1, n, (6*k)!)} \\ Seiichi Manyama, Jul 06 2019

a(n) ~ A^(-1/6) * exp(1/72 - 7*n/2 - 9*n^2/2) * n^(55/72 + 7*n/2 + 3*n^2) * 2^(1/72 + 4*n + 3*n^2) * 3^(47/72 + 7*n/2 + 3*n^2) * Pi^(n/2 - 1/3) * Gamma(1/3)^(5/3), where A = A074962 is the Glaisher-Kinkelin constant.

A271947 a(n) = Product_{k=0..n} (7*k)!.

Original entry on oeis.org

1, 5040, 439378587648000, 22448266013011335649028997120000000, 6844214664110424043644485692109939233534721371668480000000000000

Offset: 0

Vaclav Kotesovec, Apr 17 2016

nonn

The next term has 104 digits.
In general, for p > 0, Product_{k=0..n} (p*k)! = p^((n+1)*(n*p+1)/2) * (2*Pi)^((n+1)*(1-p)/2) * Product_{j=1..p} BarnesG(n+1+j/p) / BarnesG(j/p).
Equivalently, Product_{k=0..n} (p*k)! = A^(p - 1/p) * exp(1/(12*p) - p/12) * (2*Pi)^((1-p)*n/2) * p^(p*n^2/2 + (p+1)*n/2 - 1/(12*p)) * Product_{j=1..p} (BarnesG(n + 1 + j/p) / Gamma(j/p)^(j/p)), where A = A074962 is the Glaisher-Kinkelin constant.
Asymptotics: Product_{k=0..n} (p*k)! ~ exp(p/12 - (p+1)*n/2 - 3*p*n^2/4) * n^(1/4 + p/12 + 1/(12*p) + (p+1)*n/2 + p*n^2/2) * p^(1/2 + (p+1)*n/2 + p*n^2/2) * (2*Pi)^(n/2 - p/4 + 3/4) / (A^p * Product_{j=1..p} BarnesG(j/p)).
Equivalently, Product_{k=0..n} (p*k)! ~ A^(-1/p) * exp(1/(12*p) - (p+1)*n/2 - 3*p*n^2/4) * n^(1/4 + p/12 + 1/(12*p) + (p+1)*n/2 + p*n^2/2) * p^(-1/(12*p) + (p+1)*n/2 + p*n^2/2) * (2*Pi)^(n/2 + (p+1)/4) / Product_{j=1..p-1} Gamma(j/p)^(j/p), where A = A074962 is the Glaisher-Kinkelin constant.
The general formula for the product of Barnes-G functions is: Product_{j=1..p} BarnesG(j/p) = A^(1/p - p) * exp(p/12 - 1/(12*p)) * p^(1/2 + 1/(12*p)) * (2*Pi)^((1-p)/2) * Product_{j=1..p-1} Gamma(j/p)^(j/p).

Seiichi Manyama, Table of n, a(n) for n = 0..13
Eric Weisstein's World of Mathematics, Barnes G-Function
Eric Weisstein's World of Mathematics, Glaisher-Kinkelin Constant

Cf. A000178 (p=1), A098694 (p=2), A268504 (p=3), A268505 (p=4), A268506 (p=5), A271946 (p=6).

Partial products of A195391.

Mathematica
```
Table[Product[(7*k)!,{k,0,n}],{n,0,8}]
```

{a(n) = prod(k=1, n, (7*k)!)} \\ Seiichi Manyama, Jul 06 2019

a(n) ~ A^(-1/7) * exp(1/84 - 4*n - 21*n^2/4) * n^(71/84 + 4*n + 7*n^2/2) * 7^(-1/84 + 4*n + 7*n^2/2) * (2*Pi)^(n/2 + 2) / (Gamma(1/7)^(1/7) * Gamma(2/7)^(2/7) * Gamma(3/7)^(3/7) * Gamma(4/7)^(4/7) * Gamma(5/7)^(5/7) * Gamma(6/7)^(6/7)), where A = A074962 is the Glaisher-Kinkelin constant.

A262261 a(n) = Product_{k=0..n} binomial(4*k,k).

Original entry on oeis.org

1, 4, 112, 24640, 44844800, 695273779200, 93581069585203200, 110803729631663996928000, 1165466869384731418887782400000, 109720873815210197693149787062272000000, 93006053830822450607559730484293052399616000000

Offset: 0

Vaclav Kotesovec, Apr 17 2016

In general, for p > 1, Product_{k=0..n} binomial(p*k,k) ~ A^(1 + 1/(p*(p-1))) * exp(n/2 - 1/12 - 1/(12*p*(p-1))) * n^(-1/3 - n/2 - 1/(12*p*(p-1))) * (p-1)^(1/(12*(p-1)) - p*n/2 - (p-1)*n^2/2) * p^(-1/(12*p) + (p+1)*n/2 + p*n^2/2) * (2*Pi)^(-1/4 - n/2) * Product_{j=1..p-1} (Gamma(j/(p-1))^(j/(p-1)) / Gamma(j/p)^(j/p)), where A = A074962 is the Glaisher-Kinkelin constant.

Cf. A007685 (p=2), A268196 (p=3).
Cf. A000178, A098694, A268504, A268505, A268506, A271946, A271947.
Cf. A005810, A165975.

Table[Product[Binomial[4*k,k],{k,0,n}],{n,0,10}]

a(n) ~ A^(13/12) * 2^(9*n/2 + 4*n^2) * exp(n/2 - 13/144) * Gamma(1/4)^(1/2) / (Gamma(1/3)^(1/3) * 3^(11/36 + 2*n + 3*n^2/2) * Pi^(7/12 + n/2) * n^(49/144 + n/2)), where A = A074962 is the Glaisher-Kinkelin constant.

A294324 a(n) = Product_{k=0..n} (5*k + 2)!.

Original entry on oeis.org

2, 10080, 4828336128000, 1717378459351319052288000000, 1930334638180469242638816526565470371840000000000, 21019161870767674789722561439867977128887689291877548419973120000000000000000

Offset: 0

Vaclav Kotesovec, Oct 28 2017

nonn

Cf. A268506, A294319, A294321, A294323, A294325, A294326.

Table[Product[(5*k + 2)!, {k, 0, n}] , {n, 0, 10}]
FoldList[Times,(5Range[0,10]+2)!] (* Harvey P. Dale, Aug 11 2024 *)

a(n) ~ 2^(n/2 + 6/5) * 5^(5*n^2/2 + 5*n + 7/3) * n^(5*n^2/2 + 5*n + 137/60) * Pi^(n/2 + 11/10) / (A^(1/5) * (1 + sqrt(5))^(1/10) * Gamma(1/5)^(2/5) * Gamma(2/5)^(4/5) * exp(15*n^2/4 + 5*n - 1/60)), where A is the Glaisher-Kinkelin constant A074962.

A268506(n) * A294323(n) * A294324(n) * A294325(n) * A294326(n) = A000178(5*n+4).

A294325 a(n) = Product_{k=0..n} (5*k + 3)!.

Original entry on oeis.org

6, 241920, 1506440871936000, 9644797427717007797649408000000, 249337464544494851133170653103408676989829120000000000, 76020086814652932482688746849816272353956621412690696880710462996480000000000000000

Offset: 0

Vaclav Kotesovec, Oct 28 2017

nonn

Cf. A268506, A294322, A294323, A294324, A294326.

Table[Product[(5*k + 3)!, {k, 0, n}] , {n, 0, 10}]

a(n) ~ (1 + sqrt(5))^(2/5) * Gamma(2/5)^(1/5) * 2^(n/2 + 1/5) * 5^(5*n^2/2 + 6*n + 43/12) * n^(5*n^2/2 + 6*n + 203/60) * Pi^(n/2 + 3/5) / (A^(1/5) * Gamma(1/5)^(2/5) * exp(15*n^2/4 + 6*n - 1/60)), where A is the Glaisher-Kinkelin constant A074962.

A268506(n) * A294323(n) * A294324(n) * A294325(n) * A294326(n) = A000178(5*n+4).

A294326 a(n) = Product_{k=0..n} (5*k + 4)!.

Original entry on oeis.org

24, 8709120, 759246199455744000, 92358580167818066670290731008000000, 57303733451473984666829812178837795780510487674880000000000

Offset: 0

Vaclav Kotesovec, Oct 28 2017

nonn

Cf. A268506, A294323, A294324, A294325.

Table[Product[(5*k + 4)!, {k, 0, n}] , {n, 0, 10}]
FoldList[Times,(5*Range[0,5]+4)!] (* Harvey P. Dale, Sep 27 2018 *)

a(n) ~ 2^(n/2 + 1/5) * 5^(5*n^2/2 + 7*n + 29/6) * n^(5*n^2/2 + 7*n + 281/60) * Pi^(n/2 + 1/10) * Gamma(1/5)^(3/5) * Gamma(2/5)^(1/5) / (A^(1/5) * (1 + sqrt(5))^(1/10) * exp(15*n^2/4 + 7*n-1/60)), where A is the Glaisher-Kinkelin constant A074962.

A268506(n) * A294323(n) * A294324(n) * A294325(n) * A294326(n) = A000178(5*n+4).

cp's OEIS Frontend

A098694 Double-superfactorials: a(n) = Product_{k=1..n} (2k)!.

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A268504 a(n) = Product_{k=0..n} (3*k)!.

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A100734 a(n) = (5*n)!.

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A268505 a(n) = Product_{k=0..n} (4*k)!.

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A271946 a(n) = Product_{k=0..n} (6*k)!.

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A271947 a(n) = Product_{k=0..n} (7*k)!.

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A262261 a(n) = Product_{k=0..n} binomial(4*k,k).

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A294324 a(n) = Product_{k=0..n} (5*k + 2)!.

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