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.

A272244 a(n) = Product_{k=0..n} (n^2 + k^2).

Original entry on oeis.org

0, 2, 160, 21060, 4352000, 1313845000, 547573478400, 301758856490000, 212663770808320000, 186659516597629140000, 199722414913149440000000, 255947740845844788169000000, 387074162712817024892928000000, 682170272459193898736228210000000
Offset: 0

Views

Author

Vaclav Kotesovec, Apr 23 2016

Keywords

Crossrefs

Cf. A126804, A272246, A272247, A272248, A367823, A367833.
Cf. A101686, A272180, A323540, A324403.

Programs

  • Mathematica
    Table[Product[n^2+k^2,{k,0,n}],{n,0,15}]

Formula

a(n) ~ 2^(n + 1/2) * n^(2*(n+1)) / exp((4-Pi)*n/2).

A367834 a(n) = Product_{i=1..n, j=1..n} (i^8 + j^8).

Original entry on oeis.org

1, 2, 67634176, 1775927682136440882473213952, 22495149450984565292579847926810488282934424886723006835982336
Offset: 0

Views

Author

Vaclav Kotesovec, Dec 02 2023

Keywords

Comments

Next term is too long to be included.
For m > 0, Product_{j=1..n, k=1..n} (j^m + k^m) ~ c(m) * exp(n*(n+1)*s(m) - m*n*(n-2)/2) * n^(m*(n^2 - 1/4 - v)), where v = 0 if m > 1 and v = 1/6 if m = 1, s(m) = Sum_{j>=1} (-1)^(j+1)/(j*(1 + m*j)) and c(m) is a constant (dependent only on m). Equivalently, s(m) = log(2) - HurwitzLerchPhi(-1, 1, 1 + 1/m).
c(1) = A / (2^(1/12) * exp(1/12) * sqrt(Pi)).
c(2) = exp(Pi/12) * Gamma(1/4) / (2^(5/4) * Pi^(5/4)).
c(3) = A * 3^(1/6) * exp(Pi/(6*sqrt(3)) - 1/12) * Gamma(1/3)^2 / (2^(7/4) * Pi^(13/6)), where A = A074962 is the Glaisher-Kinkelin constant.
c(4) = A306620.

Crossrefs

Cf. A079478 (m=1), A324403 (m=2), A324426 (m=3), A324437 (m=4), A324438 (m=5), A324439 (m=6), A324440 (m=7).
Cf. A306620, A367670, A367833.

Programs

  • Mathematica
    Table[Product[i^8 + j^8, {i, 1, n}, {j, 1, n}], {n, 0, 6}]
  • Python
    from math import prod, factorial
def A367834(n): return (prod(i**8+j**8 for i in range(1,n) for j in range(i+1,n+1))*factorial(n)**4)**2<Chai Wah Wu, Dec 02 2023

Formula

For n>0, a(n)/a(n-1) = A367833(n)^2 / (2*n^24).
a(n) ~ c * 2^(n*(n+1)) * (1 + 1/(sqrt(1 - 1/sqrt(2)) - 1/2))^(sqrt(2 + sqrt(2))*n*((n+1)/2)) * (1 + 1/(sqrt(1 + 1/sqrt(2)) - 1/2))^(sqrt(2 - sqrt(2))*n*((n+1)/2)) * (n^(8*n^2 - 2) / exp(12*n^2 - Pi*sqrt(1 + 1/sqrt(2))*n*(n+1))), where c = 0.043985703178712025347328240881106818917398444790454628282522057393529338998...

A272246 a(n) = Product_{k=0..n} (n^3 + k^3).

Original entry on oeis.org

0, 2, 1152, 1428840, 3488808960, 15044494500000, 105235903511101440, 1119277024472896248960, 17216259547948971039129600, 368066786222106315186876633600, 10591209807103301277597696000000000, 399472472359100444604916002033020774400
Offset: 0

Views

Author

Vaclav Kotesovec, Apr 23 2016

Keywords

Crossrefs

Cf. A126804, A272244, A272247, A272248, A367823, A367833.
Cf. A255433, A323541, A324426.

Programs

  • Mathematica
    Table[Product[n^3+k^3,{k,0,n}],{n,0,12}]

Formula

a(n) ~ 2^(2*n + 1/2) * n^(3*n + 3) / exp((3 - Pi/sqrt(3))*n).

A272247 a(n) = Product_{k=0..n} (n^4 + k^4).

Original entry on oeis.org

0, 2, 8704, 104372388, 3087748038656, 194985808028125000, 23467500289618753093632, 4938279594477505466022892304, 1699491802948673617630927695904768, 907214902722906584628050661111614570016, 719684491044699824651608981274624000000000000
Offset: 0

Views

Author

Vaclav Kotesovec, Apr 23 2016

Keywords

Crossrefs

Cf. A126804, A272244, A272246, A272248, A367823, A367833.
Cf. A255434, A323542.

Programs

  • Mathematica
    Table[Product[n^4+k^4,{k,0,n}],{n,0,10}]

Formula

a(n) ~ 2^(n+1/2) * (1+sqrt(2))^(sqrt(2)*n) * n^(4*n + 4) / exp((4 - Pi/sqrt(2))*n).

A272248 a(n) = Product_{k=0..n} (n^5 + k^5).

Original entry on oeis.org

0, 2, 67584, 7924375800, 2876035930521600, 2693451205324687500000, 5648896640332217707816550400, 23819277009290664033936067933468800, 185754160490281505676324140907107450880000, 2507604631016507710974687639612411760216253760000
Offset: 0

Views

Author

Vaclav Kotesovec, Apr 23 2016

Keywords

Comments

In general, for p>=1, Product_{k=0..n} (n^p + k^p) ~ sqrt(2) * n^(p*(n+1)) * exp(n*Sum_{j>=1} (-1)^(j+1) / (j*(1 + j*p))).

Crossrefs

Cf. A126804, A272244, A272246, A272247, A367823, A367833.
Cf. A255435, A323543, A324438.

Programs

  • Mathematica
    Table[Product[n^5+k^5,{k,0,n}],{n,0,10}]

Formula

a(n) ~ 2^(2*n+1/2) * phi^(sqrt(5)*n) * n^(5*n+5) / exp((5-sqrt(phi)*Pi/5^(1/4))*n), where phi = A001622 = (1+sqrt(5))/2 is the golden ratio.

A367823 a(n) = Product_{k=0..n} (n^6 + k^6).

Original entry on oeis.org

0, 2, 532480, 615291760980, 2759348178649088000, 38607000141072009765625000, 1421393314362014000255258433945600, 120987688662917113214734283836109985530000, 21538956798613753302336535534471908360548515840000, 7407676630843157974199152503244776880017496531101658740000
Offset: 0

Views

Author

Vaclav Kotesovec, Dec 02 2023

Keywords

Crossrefs

Cf. A126804, A272244, A272246, A272247, A272248, A324439, A367833.

Programs

  • Mathematica
    Table[Product[n^6 + k^6, {k, 0, n}], {n, 0, 10}]
  • PARI
    a(n) = prod(k=0, n, n^6 + k^6); \\ Michel Marcus, Dec 02 2023

Formula

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

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