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.

A324439 a(n) = Product_{i=1..n, j=1..n} (i^6 + j^6).

Original entry on oeis.org

1, 2, 1081600, 528465082730906880000, 29276520893554373473343522853366005760000000000, 5719545329208791496596894540018824083491259163047733746620041978183680000000000000000
Offset: 0

Views

Author

Vaclav Kotesovec, Feb 28 2019

Keywords

Crossrefs

Programs

  • Maple
    a:= n-> mul(mul(i^6 + j^6, i=1..n), j=1..n):
    seq(a(n), n=0..5);  # Alois P. Heinz, Nov 26 2023
  • Mathematica
    Table[Product[i^6 + j^6, {i, 1, n}, {j, 1, n}], {n, 1, 6}]
  • Python
    from math import prod, factorial
    def A324439(n): return (prod(i**6+j**6 for i in range(1,n) for j in range(i+1,n+1))*factorial(n)**3)**2<Chai Wah Wu, Nov 26 2023

Formula

a(n) ~ c * 2^(n*(n+1)) * (2 + sqrt(3))^(sqrt(3)*n*(n+1)) * exp(Pi*n*(n+1) - 9*n^2) * n^(6*n^2 - 3/2), where c = 0.104143806044091748191387307161835081649...
a(n) = A324403(n) * A367668(n). - Vaclav Kotesovec, Dec 01 2023
For n>0, a(n)/a(n-1) = A367823^2 / (2*n^18). - Vaclav Kotesovec, Dec 02 2023

Extensions

a(n)=1 prepended by Alois P. Heinz, Nov 26 2023

A367550 a(n) = Product_{i=1..n, j=1..n} (i^4 + i^2*j^2 + j^4).

Original entry on oeis.org

3, 63504, 2260442279270448, 3379470372507391964272022793486336, 2097229364987262298214192667129919538956418868293588090880000
Offset: 1

Views

Author

Vaclav Kotesovec, Nov 22 2023

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Product[Product[i^4 + i^2*j^2 + j^4, {i, 1, n}], {j, 1, n}], {n, 1, 10}]
  • Python
    from math import prod, factorial
    def A367550(n): return (prod((i2:=i**2)*(i2+(j2:=j**2))+j2**2 for i in range(1,n) for j in range(i+1,n+1))*factorial(n)**2)**2*3**n # Chai Wah Wu, Nov 22 2023

Formula

a(n) = A367542(n) * A367543(n).
a(n) ~ Gamma(1/3)^3 * 3^(3*n*(n+1)/2 + 7/12) * n^(4*n^2 - 1) / (8*Pi^3 * exp(6*n^2 - (6*n*(n+1) + 1)*Pi/(4*sqrt(3)))).

A203675 Vandermonde sequence using x^2 - xy + y^2 applied to (1,4,9,...,n^2).

Original entry on oeis.org

1, 13, 57889, 560058939856, 42130404012097952586256, 65111467563626175389271488157658681344, 4528499444374253250530486688998183592108605307719698157568
Offset: 1

Views

Author

Clark Kimberling, Jan 04 2012

Keywords

Comments

See A093883 for a discussion and guide to related sequences.

Crossrefs

Programs

  • Mathematica
    f[j_] := j^2; z = 12;
    u[n_] := Product[f[j]^2 - f[j] f[k] + f[k]^2, {j, 1, k - 1}]
    v[n_] := Product[u[n], {k, 2, n}]
    Table[v[n], {n, 1, z}]          (* A203675 *)
    Table[v[n + 1]/v[n], {n, 1, z}] (* A203676 *)

Formula

a(n) ~ c * (2 + sqrt(3))^(sqrt(3)*n*(n+1)/2) * n^(2*n^2 - 2*n - 3/2) / exp(3*n^2 - Pi*n*(n+1)/4 - 2*n), where c = 0.07463795295314976973866568785704370572893158254239607676544741150586459722... - Vaclav Kotesovec, Nov 25 2023

A367670 a(n) = Product_{i=1..n, j=1..n} (i^8 + i^4*j^4 + j^8).

Original entry on oeis.org

3, 171714816, 9817265089769041882465383168, 351690857158733335833718073682368165890982417955022627663773696
Offset: 1

Views

Author

Vaclav Kotesovec, Nov 26 2023

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Product[Product[i^8 + i^4*j^4 + j^8, {i, 1, n}], {j, 1, n}], {n, 1, 7}]
  • Python
    from math import prod, factorial
    def A367670(n): return (prod((k:=j**4)**2+(m:=i**4)*(m+k) for i in range(1,n) for j in range(i+1,n+1))*factorial(n)**4)**2*3**n # Chai Wah Wu, Nov 26 2023

Formula

a(n) = A367550(n) * A367668(n).
a(n) = A367542(n) * A367543(n) * A367668(n).
a(n) ~ c * 3^(3*n*(n+1)/2) * (2 + sqrt(3))^(sqrt(3)*n*(n+1)) * n^(8*n^2 - 2) / exp(12*n^2 - Pi*(1 + sqrt(3))*n*(n+1)/2), where c = 0.05091893538977858024246640150391280389386566805866250210433631511020673755...

A367679 a(n) = Product_{i=1..n, j=1..n} (i^4 - i^3*j + i^2*j^2 - i*j^3 + j^4).

Original entry on oeis.org

1, 1936, 1765124816400, 19271059559619728900751360000, 25048411180596698786915756280274804766474649600000000, 23045227505577134384745253646275782332295626096040088365089618773238077194240000000000
Offset: 1

Views

Author

Vaclav Kotesovec, Nov 26 2023

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Product[i^4 - i^3*j + i^2*j^2 - i*j^3 + j^4, {i, 1, n}, {j, 1, n}], {n, 1, 6}]
  • Python
    from math import prod, factorial
    def A367679(n): return (prod(i*(i*(i*(i-j)+j**2)-j**3)+j**4 for i in range(1,n) for j in range(i+1,n+1))*factorial(n)**2)**2 # Chai Wah Wu, Nov 26 2023

Formula

a(n) = A324438(n) / A079478(n).
a(n) ~ c * n^(4*n^2 - 5/6) * phi^(sqrt(5)*n*(n+1)) / exp(6*n^2 - sqrt(phi)*Pi*n*(n+1)/5^(1/4)), where phi = A001622 is the golden ratio and c = 0.2505211390193028244009922677012518708897316924498037078191143761182342931773594...
Showing 1-5 of 5 results.