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 11-15 of 15 results.

A208190 Number of distinct 5-colored necklaces with n beads per color.

Original entry on oeis.org

1, 24, 11352, 11211216, 15277017432, 24934429725024, 45695805591924048, 90784545100668913392, 191417861328837588057432, 422458626725600682518100816, 966695515158024410709527456352, 2277925055026596846727033776223440, 5499697195473757755182168765034005328
Offset: 0

Views

Author

Alois P. Heinz, Feb 24 2012

Keywords

Examples

			a(0) =  1: the empty necklace.
a(1) = 24: {01234, 01243, ..., 04321}.
		

Crossrefs

Column k=5 of A208183.

Programs

  • Maple
    with(numtheory):
    a:= n-> `if`(n=0, 1, add(phi(n/d) * (5*d)!/(d!^5 *5*n), d=divisors(n))):
    seq(a(n), n=0..14);

Formula

a(n) = Sum_{d|n} phi(n/d)*(5*d)!/(d!^5*5*n) if n>0 and a(0) = 1.
a(n) ~ 5^(5*n-1/2) / (4 * Pi^2 * n^3). - Vaclav Kotesovec, Aug 23 2015

A208191 Number of distinct 6-colored necklaces with n beads per color.

Original entry on oeis.org

1, 120, 623760, 7623616080, 135277939358160, 2961088201992945120, 74171603795480180204640, 2041012695880532470281654960, 60192781171721237282811209918160, 1872173374511564116503341160073744080, 60735890264793885272652711347090416733760
Offset: 0

Views

Author

Alois P. Heinz, Feb 24 2012

Keywords

Examples

			a(0) =   1: the empty necklace.
a(1) = 120: {012345, 012354, ..., 054321}.
		

Crossrefs

Column k=6 of A208183.

Programs

  • Maple
    with(numtheory):
    a:= n-> `if`(n=0, 1, add(phi(n/d) *(6*d)!/(d!^6 *6*n), d=divisors(n))):
    seq(a(n), n=0..12);

Formula

a(n) = Sum_{d|n} phi(n/d)*(6*d)!/(d!^6*6*n) if n>0 and a(0) = 1.
a(n) ~ 6^(6*n-1/2) / (2^(5/2) * Pi^(5/2) * n^(7/2)). - Vaclav Kotesovec, Aug 23 2015

A208192 Number of distinct 7-colored necklaces with n beads per color.

Original entry on oeis.org

1, 720, 48648960, 8690922240480, 2374127830286012160, 823940558733748910598720, 333504309246734399617946903040, 150277870737901828652705825755721760, 73288704867601350013562616043249358012160, 37980016035292737119901943600678905519608160480
Offset: 0

Views

Author

Alois P. Heinz, Feb 24 2012

Keywords

Examples

			a(0) =   1: the empty necklace.
a(1) = 720: {0123456, 0123465, ..., 0654321}.
		

Crossrefs

Column k=7 of A208183.

Programs

  • Maple
    with(numtheory):
    a:= n-> `if`(n=0, 1, add(phi(n/d) *(7*d)!/(d!^7 *7*n), d=divisors(n))):
    seq(a(n), n=0..12);

Formula

a(n) = Sum_{d|n} phi(n/d)*(7*d)!/(d!^7*7*n) if n>0 and a(0) = 1.
a(n) ~ 7^(7*n-1/2) / (8 * Pi^3 * n^4). - Vaclav Kotesovec, Aug 23 2015

A208193 Number of distinct 8-colored necklaces with n beads per color.

Original entry on oeis.org

1, 5040, 5108105520, 15391623287043360, 74701932179186551241520, 474389544274867071519255599040, 3581026866351385580856518554063502880, 30495546426686489361833408314854897254404320, 283839436431731355577562936415156522873876247241520
Offset: 0

Views

Author

Alois P. Heinz, Feb 24 2012

Keywords

Comments

In general, column k > 1 of A208183 is asymptotic to k^(k*n-1/2) / ((2*Pi)^((k-1)/2) * n^((k+1)/2)). - Vaclav Kotesovec, Aug 23 2015

Examples

			a(0) =    1: the empty necklace.
a(1) = 5040: {01234567, 01234576, ..., 07654321}.
		

Crossrefs

Column k=8 of A208183.

Programs

  • Maple
    with(numtheory):
    a:= n-> `if`(n=0, 1, add(phi(n/d) *(8*d)!/(d!^8 *8*n), d=divisors(n))):
    seq(a(n), n=0..10);

Formula

a(n) = Sum_{d|n} phi(n/d)*(8*d)!/(d!^8*8*n) if n>0 and a(0) = 1.
a(n) ~ 8^(8*n-1/2) / ((2*Pi)^(7/2) * n^(9/2)). - Vaclav Kotesovec, Aug 23 2015

A252765 Number of distinct n-colored necklaces with n beads per color.

Original entry on oeis.org

1, 1, 2, 188, 3941598, 24934429725024, 74171603795480180204640, 150277870737901828652705825755721760, 283839436431731355577562936415156522873876247241520, 655934428473920614716696820356119117524334608980167506174657536026880
Offset: 0

Views

Author

Alois P. Heinz, Dec 21 2014

Keywords

Crossrefs

Main diagonal of A208183.

Programs

  • Maple
    with(numtheory):
    a:= n-> `if`(n=0, 1, add(phi(n/d)*(n*d)!/(d!^n*n^2), d=divisors(n))):
    seq(a(n), n=0..10);
  • Mathematica
    a[n_] := If[n == 0, 1, DivisorSum[n, EulerPhi[n/#]*(n*#)!/(#!^n*n^2)&]];
    Table[a[n], {n, 0, 10}] (* Jean-François Alcover, Mar 25 2017, translated from Maple *)

Formula

a(n) = Sum_{d|n} phi(n/d)*(n*d)!/(d!^k*n^2) for n>0, a(0) = 1.
From Vaclav Kotesovec, Aug 23 2015: (Start)
a(n) ~ (n^2)! / (n^2 * (n!)^n).
a(n) ~ n^(n^2 - n/2 - 1) / (exp(1/12) * (2*Pi)^((n-1)/2)).
(End)
Previous Showing 11-15 of 15 results.