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 1-2 of 2 results.

A270842 Number of nonisomorphic edge colorings of the Petersen graph with at most n colors.

Original entry on oeis.org

1, 396, 123786, 9002912, 254721400, 3920311044, 39571426713, 293231076608, 1715840171595, 8333541708700, 34810892718492, 128392921513440, 426551317876970, 1296405100924948, 3649123762524675, 9607693522053120, 23853550135649477, 56222046462953772
Offset: 1

Views

Author

Marko Riedel, Mar 24 2016

Keywords

Comments

These are not colorings in the strict sense, since there is no requirement that adjacent edges have different colors. - N. J. A. Sloane, Mar 28 2016

Crossrefs

Cf. A270843, A063843. See A159233 for edge colorings where adjacent edges must have different colors.

Programs

  • PARI
    a(n) = n^15/120 + 5*n^9/24 + 5*n^5/12 + 11*n^3/30; \\ Altug Alkan, Mar 25 2016

Formula

Cycle index of the automorphisms acting on the edges is (1/120)*S[1]^15+(5/24)*S[2]^6*S[1]^3+(1/4)*S[4]^3*S[2]*S[1]+(1/6)*S[3]^5+(1/6)*S[3]*S[6]^2+(1/5)*S[5]^3.
a(n) = n^15/120 + 5*n^9/24 + 5*n^5/12 + 11*n^3/30.
G.f.: x*(1 + 380*x + 117570*x^2 + 7069296*x^3 + 125309188*x^4 + 856514276*x^5 + 2594956089*x^6 + 3729352800*x^7 + 2594956089*x^8 + 856514276*x^9 + 125309188*x^10 + 7069296*x^11 + 117570*x^12 + 380*x^13 + x^14) / (1 - x)^16. - Colin Barker, Dec 24 2017

A296913 Number of ways to properly color the Petersen graph using n colors.

Original entry on oeis.org

0, 0, 120, 12960, 332880, 3868080, 27767880, 144278400, 594347040, 2055598560, 6202551960, 16774966560, 41473626480, 95135323920, 204803912040, 417515696640, 811858751040, 1514650599360, 2724410748600, 4743687388320, 8022734847120, 13217533726320, 21265702652040, 33484472926080, 51695588642400, 78382758698400, 116888127197400
Offset: 1

Views

Author

N. J. A. Sloane, Dec 22 2017

Keywords

Crossrefs

Programs

  • Mathematica
    Array[#^10 - 15 #^9 + 105 #^8 - 455 #^7 + 1353 #^6 - 2861 #^5 + 4275 #^4 - 4305 #^3 + 2606 #^2 - 704 # &, 27] (* Michael De Vlieger, Dec 23 2017 *)
    Rest@ CoefficientList[ Series[-120 x^3 (139x^7 +1693x^6 +7269x^5 +11905x^4 +7495x^3 +1641x^2 +97x +1)/(x -1)^11, {x, 0, 23}], x] (* or *)
    LinearRecurrence[{11, -55, 165, -330, 462, -462, 330, -165, 55, -11, 1}, {0, 0, 120, 12960, 332880, 3868080, 27767880, 144278400, 594347040, 2055598560, 6202551960}, 23] (* Robert G. Wilson v, Dec 24 2017 *)
  • PARI
    concat(vector(2), Vec(120*x^3*(1 + 97*x + 1641*x^2 + 7495*x^3 + 11905*x^4 + 7269*x^5 + 1693*x^6 + 139*x^7) / (1 - x)^11 + O(x^40))) \\ Colin Barker, Dec 24 2017

Formula

a(n) = n^10 - 15*n^9 + 105*n^8 - 455*n^7 + 1353*n^6 - 2861*n^5 + 4275*n^4 - 4305*n^3 + 2606*n^2 - 704*n.
From Colin Barker, Dec 24 2017: (Start)
G.f.: 120*x^3*(1 + 97*x + 1641*x^2 + 7495*x^3 + 11905*x^4 + 7269*x^5 + 1693*x^6 + 139*x^7) / (1 - x)^11.
a(n) = 11*a(n-1) - 55*a(n-2) + 165*a(n-3) - 330*a(n-4) + 462*a(n-5) - 462*a(n-6) + 330*a(n-7) - 165*a(n-8) + 55*a(n-9) - 11*a(n-10) + a(n-11) for n>11.
(End)
Showing 1-2 of 2 results.