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.

A338982 Number of chiral pairs of colorings of the 120 dodecahedral facets of the 4-D 120-cell (or 120 vertices of the 4-D 600-cell) using exactly n colors.

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%I A338982 #18 Dec 20 2020 11:07:20
%S A338982 0,0,92307499707128546879177569498768,
%T A338982 124792381938502167386992798774696507063550726794469211,
%U A338982 122697712831831745940423455373835049129541140194826165569091574960692
%N A338982 Number of chiral pairs of colorings of the 120 dodecahedral facets of the 4-D 120-cell (or 120 vertices of the 4-D 600-cell) using exactly n colors.
%C A338982 Each member of a chiral pair is a reflection but not a rotation of the other. The Schläfli symbols of the 120-cell and 600-cell are {5,3,3} and {3,3,5} respectively. They are mutually dual. For n>120, a(n) = 0.
%C A338982 Sequences for other elements of the 120-cell and 600-cell are not suitable for the OEIS as the first significant datum is too big. We provide generating functions here using bp(j) = Sum_{k=1..j} k! * S2(j,k) * x^k.
%C A338982 For the 600 facets of the 600-cell (vertices of the 120-cell), the generating function is bp(20)/15 + bp(30)/10 + bp(40)/15 + bp(50)/12 - 17*bp(60)/300 - bp(66)/10 + bp(100)/360 - bp(104)/18 - bp(114)/12 + 13*bp(120)/300 + bp(150)/240 - bp(152)/8 + bp(200)/360 + bp(208)/36 - 59*bp(300)/14400 + bp(302)/32 - bp(330)/240 + bp(600)/14400.
%C A338982 For the 720 pentagonal faces of the 120-cell (edges of the 600-cell), the generating function is bp(24)/15 + bp(36)/10 + bp(48)/15 + bp(60)/12 + 7*bp(72)/300 - 2*bp(76)/25 - bp(84)/10 - 19*bp(120)/360 - bp(132)/12 + 7*bp(144)/300 + bp(152)/50 + bp(180)/240 - bp(182)/8 + 11*bp(240)/360 - 59*bp(360)/14400 + bp(364)/32 - bp(396)/240 + bp(720)/14400.
%C A338982 For the 1200 edges of the 120-cell (triangular faces of the 600-cell), the generating function is bp(40)/15 + bp(60)/10 + bp(80)/15 + bp(100)/12 - 17*bp(120)/300 - bp(128)/10 + bp(200)/360 - bp(202)/18 - bp(216)/12 + 13*bp(240)/300 + bp(300)/240 - bp(302)/8 + bp(400)/360 + bp(404)/36 - 59*bp(600)/14400 + bp(604)/32 - bp(640)/240 + bp(1200)/14400.
%H A338982 Robert A. Russell, <a href="/A338982/b338982.txt">Table of n, a(n) for n = 0..120</a>
%F A338982 A338966(n) = Sum_{j=2..Min(n,120)} a(n) * binomial(n,j).
%F A338982 a(n) = A338980(n) - A338981(n) = (A338980(n) - A338983(n)) / 2 = A338981(n) - A338983(n).
%F A338982 G.f.: bp(4)/15 + bp(6)/10 + bp(8)/15 + bp(10)/12 + 7*bp(12)/300 + bp(16)/50 - bp(17)/10 - bp(19)/10 + bp(20)/360 + bp(22)/36 - bp(23)/12 + 7*bp(24)/300 - bp(27)/12 + bp(30)/240 - bp(31)/8 + bp(32)/50 + bp(40)/360 + bp(44)/36 + bp(60)/14400 - bp(61)/240 + bp(62)/32 - bp(75)/240 + bp(120)/14400, where bp(j) = Sum_{k=1..j} k! * S2(j,k) * x^k and S2(j,k) is the Stirling subset number, A008277.
%t A338982 bp[j_] := Sum[k! StirlingS2[j, k] x^k, {k, j}] (*binomial series*)
%t A338982 CoefficientList[bp[4]/15+bp[6]/10+bp[8]/15+bp[10]/12+7bp[12]/300+bp[16]/50-bp[17]/10-bp[19]/10+bp[20]/360+bp[22]/36-bp[23]/12+7bp[24]/300-bp[27]/12+bp[30]/240-bp[31]/8+bp[32]/50+bp[40]/360+bp[44]/36+bp[60]/14400-bp[61]/240+bp[62]/32-bp[75]/240+bp[120]/14400,x]
%Y A338982 Cf. A338980 (oriented), A338981 (unoriented), A338983 (achiral), A338966 (up to n colors), A000389 (5-cell), A337954 (8-cell vertices, 16-cell facets), A234249 (16-cell vertices, 8-cell facets), A338950 (24-cell).
%K A338982 fini,nonn,easy
%O A338982 0,3
%A A338982 _Robert A. Russell_, Dec 13 2020