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.

Previous Showing 11-17 of 17 results.

A255360 Product_{k=0..n} (k^5)!.

Original entry on oeis.org

1, 1, 263130836933693530167218012160000000
Offset: 0

Views

Author

Vaclav Kotesovec, Feb 21 2015

Keywords

Comments

The next term a(3) has 512 digits.
In general (for m>1), product_{k=0..n} (k^m)! ~ c(m) * (2*Pi)^(n/2) * n^(m*(1/4 + n/2 + B(m+1)/(m+1) + (sum_{j=1..n} j^m) )) * exp(-m*n/2 - m*n^(m+1)/(m+1)^2 - (sum_{j=1..n} j^m) + m * (sum_{j=1..m-1} 1/(j+1) * B(j+1) * binomial(m, j) * n^(m-j) * (sum_{i=0..j-1} 1/(m-i)) )), where c(m) is a constant and B(n) is the Bernoulli number A027641(n)/A027642(n).

Crossrefs

Programs

  • Mathematica
    Table[Product[(k^5)!, {k, 0, n}], {n, 0, 4}]
    Table[Product[j^(n - Ceiling[j^(1/5)] + 1), {j, 1, n^5}], {n, 0, 4}] (* Vaclav Kotesovec, Apr 25 2024 *)

Formula

a(n) ~ c * n^(80/63 + 5*n/2 - 5*n^2/12 + 25*n^4/12 + 5*n^5/2 + (5*n^6)/6) * (2*Pi)^(n/2) / exp(5*n/2 + 35*n^2/144 + n^5/2 + 11*n^6/36), where c = A255439 = 11.354954749729782312106... .
a(n) = Product_{j=1..n^5} j^(n - ceiling(j^(1/5)) + 1). - Vaclav Kotesovec, Apr 25 2024

A317747 Numerator of the coefficient of z^(-n) in the Stirling-like asymptotic expansion of Product_{z=1..n} z^(z^2).

Original entry on oeis.org

1, -1, 1, 259193, -1036793, -201551328007, 9137074752049, 9142431862033871923, -11105299580705049589, -11003865617473929216508154207, 114467620015003245418244743007, 32505236416490926096399421788847363, -254505521478572052318535393350091231, -1828472168539763642032546635313363411876021
Offset: 0

Views

Author

Seiichi Manyama, Sep 01 2018

Keywords

Comments

1^(1^2)*2^(2^2)*...*n^(n^2) ~ A_2*n^(n^3/3+n^2/2+n/6)*exp(-n^3/9+n/12)*(Sum_{k>=0} b(k)/n^k)^n, where A_2 is the second Bendersky constant.
a(n) is the numerator of b(n).

Examples

			1^(1^2)*2^(2^2)*...*n^(n^2) ~ A_2*n^(n^3/3+n^2/2+n/6)*exp(-n^3/9+n/12)*(1 - 1/(360*n) + 1/(259200*n^2) + 259193/(1959552000*n^3) - 1036793/(2821754880000*n^4) - 201551328007/(5079158784000000*n^5) + ... ).
		

Crossrefs

Product_{z=1..n} z^(z^m): A001163/A001164 (m=0), A143475/A143476 (m=1), A317747/A317796 (m=2).
Cf. A051675, A243262 (A_2).

Formula

Let B_n be the Bernoulli number, and define the sequence {c_n} by the recurrence
c_0 = 1, c_n = (2/n) * Sum_{k=0..n-1} B_{n-k+3}*c_k/((n-j+1)*(n-k+2)*(n-k+3)) for n > 0.
a(n) is the numerator of c_n.

A317796 Denominator of the coefficient of z^(-n) in the Stirling-like asymptotic expansion of Product_{z=1..n} z^(z^2).

Original entry on oeis.org

1, 360, 259200, 1959552000, 2821754880000, 5079158784000000, 76796880814080000000, 304115648023756800000000, 125121866615488512000000000, 258236518070374430146560000000000, 929651465053347948527616000000000000, 334674527419205261469941760000000000000, 920050700832433373350094438400000000000000
Offset: 0

Views

Author

Seiichi Manyama, Sep 01 2018

Keywords

Comments

1^(1^2)*2^(2^2)*...*n^(n^2) ~ A_2*n^(n^3/3+n^2/2+n/6)*exp(-n^3/9+n/12)*(Sum_{k>=0} b(k)/n^k)^n, where A_2 is the second Bendersky constant.
a(n) is the denominator of b(n).

Examples

			1^(1^2)*2^(2^2)*...*n^(n^2) ~ A_2*n^(n^3/3+n^2/2+n/6)*exp(-n^3/9+n/12)*(1 - 1/(360*n) + 1/(259200*n^2) + 259193/(1959552000*n^3) - 1036793/(2821754880000*n^4) - 201551328007/(5079158784000000*n^5) + ... ).
		

Crossrefs

Product_{z=1..n} z^(z^m): A001163/A001164 (m=0), A143475/A143476 (m=1), A317747/A317796 (m=2).
Cf. A051675, A243262 (A_2).

Formula

Let B_n be the Bernoulli number, and define the sequence {c_n} by the recurrence
c_0 = 1, c_n = (2/n) * Sum_{k=0..n-1} B_{n-k+3}*c_k/((n-j+1)*(n-k+2)*(n-k+3)) for n > 0.
a(n) is the denominator of c_n.

A330716 n-th Gosper hyperfactorial of n.

Original entry on oeis.org

1, 1, 16, 1952152956156672
Offset: 0

Views

Author

Greg Huber, Dec 27 2019

Keywords

Comments

Gosper's m-th hyperfactorial of n is the product 1^(1^m)*2^(2^m)*3^(3^m)*...*n^(n^m).
The 0th hyperfactorial is the factorial function.

Examples

			n=3: a(3) = 1^(1^3)*2^(2^3)*3^(3^3) = 2^8 * 3^27.
a(4) has 198 decimal digits and a(5) has 2927 digits.
		

References

  • R. W. Gosper, "Fac Fun" (ca. 1979).

Crossrefs

Cf. A000142, A002109, A051675, A255321, A255323, A255344 (0th through 5th Gosper hyperfactorials, respectively).

Programs

  • Mathematica
    nmax:=3; Table[Product[i^(i^n),{i,1,n}],{n,0,nmax}] (* Stefano Spezia, Dec 29 2019 *)

A290770 a(n) = Product_{k=1..n} k^(2*k).

Original entry on oeis.org

1, 1, 16, 11664, 764411904, 7464960000000000, 16249593066946560000000000, 11020848942410302096869949440000000000, 3102093199396597590886754340698424229232640000000000, 465607547420733489126893933985879279492195953053596584509440000000000
Offset: 0

Views

Author

Ilya Gutkovskiy, Aug 10 2017

Keywords

Crossrefs

Programs

  • Magma
    [1] cat [(&*[k^(2*k): k in [1..n]]): n in [1..10]]; // G. C. Greubel, Oct 14 2018
  • Mathematica
    Table[Product[k^(2 k), {k, 1, n}], {n, 0, 9}]
    Table[Hyperfactorial[n]^2, {n, 0, 9}]
    Table[n!^(2 n)/BarnesG[n + 1]^2, {n, 0, 9}]
  • PARI
    a(n) = prod(k=1, n, k^(2*k)) \\ Felix Fröhlich, Aug 10 2017
    

Formula

a(n) = A002109(n)^2.
a(n) = A185141(n)/A000178(n-1)^2 for n > 0.
a(n) = (n!)^(2*n)/G(n+1)^2, where G() is the Barnes G-function.
a(n) ~ A^2*exp(-n^2/2)*n^(n*(n+1))*n^(1/6), where A is the Glaisher-Kinkelin constant (A074962).

A255403 Product_{k=1..n} (k^k)!.

Original entry on oeis.org

1, 24, 261332866810040451858432000000
Offset: 1

Views

Author

Vaclav Kotesovec, Feb 22 2015

Keywords

Comments

The next term (a(4)) has 537 digits.

Crossrefs

Programs

  • Mathematica
    Table[Product[(k^k)!, {k, 1, n}], {n, 1, 4}]

A372150 a(n) = Product_{k=1..n} k!^(k^2).

Original entry on oeis.org

1, 1, 16, 161243136, 1953714516870533385423459188736, 18637697331204402735774894643901575833450808531469488619520000000000000000000000000
Offset: 0

Views

Author

Vaclav Kotesovec, Apr 20 2024

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Product[k!^(k^2), {k, 1, n}], {n, 0, 6}]

Formula

a(n) ~ (2*Pi)^(n^3/6 + n^2/4 + n/12) * n^(n^4/4 + 2*n^3/3 + n^2/2 + n/12 - 1/90) / (A^(1/6) * exp(5*n^4/16 + 5*n^3/9 + n^2/8 - n/12 - zeta(3)/(8*Pi^2) - zeta'(-3)/3 - 13/720)), where A is the Glaisher-Kinkelin constant A074962, zeta(3) = A002117, zeta'(-3) = A259068.
Previous Showing 11-17 of 17 results.