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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.

A338950 Number of chiral pairs of colorings of the 24 octahedral facets (or 24 vertices) of the 4-D 24-cell using subsets of a set of n colors.

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%I A338950 #13 Mar 10 2024 13:37:16
%S A338950 12232,241146903,243616903380,51700252145825,4112117375683170,
%T A338950 166286156041490247,4099088542944703728,69240138924298950135,
%U A338950 868045130573811864300,8550057218442459279340,69007402402972868503812
%N A338950 Number of chiral pairs of colorings of the 24 octahedral facets (or 24 vertices) of the 4-D 24-cell using subsets of a set of n colors.
%C A338950 Each member of a chiral pair is a reflection but not a rotation of the other. The Schläfli symbol of the 24-cell is {3,4,3}. It is self-dual.
%H A338950 Robert A. Russell, <a href="/A338950/b338950.txt">Table of n, a(n) for n = 2..30</a>
%H A338950 <a href="/index/Rec#order_25">Index entries for linear recurrences with constant coefficients</a>, signature (25, -300, 2300, -12650, 53130, -177100, 480700, -1081575, 2042975, -3268760, 4457400, -5200300, 5200300, -4457400, 3268760, -2042975, 1081575, -480700, 177100, -53130, 12650, -2300, 300, -25, 1).
%F A338950 a(n) = (96*n^2 + 144*n^3 - 48*n^4 - 52*n^6 - 228*n^7 - 24*n^8 + 36*n^9 + 21*n^12 + 60*n^13 + 18*n^14 - 12*n^15 - 12*n^18 + n^24) / 1152.
%F A338950 a(n) = 12232*C(n,2) + 241110207*C(n,3) + 242652389160*C(n,4) + 50484578975635*C(n,5) + 3805565293604340*C(n,6) + 138578521555036815*C(n,7) + 2881060406691096840*C(n,8) + 37995709352029326765*C(n,9) + 340998954354320550750*C(n,10) + 2186417251809922893300*C(n,11) + 10365972799754686653000*C(n,12) + 37236906263669699386800*C(n,13) + 103077047681129825503200*C(n,14) + 222282209861028829512000*C(n,15) + 375541963275099452832000*C(n,16) + 497391179860822639392000*C(n,17) + 513995707264282955712000*C(n,18) + 409785508676334510720000*C(n,19) + 247034122336026305280000*C(n,20) + 108861226736398456320000*C(n,21) + 33078014473191367680000*C(n,22) + 6193712343691192320000*C(n,23) + 538583682060103680000*C(n,24), where the coefficient of C(n,k) is the number of chiral pairs of colorings using exactly k colors.
%F A338950 a(n) = A338948(n) - A338949(n) = (A338948(n) - A338951(n)) / 2 = A338949(n) - A338951(n).
%t A338950 Table[(96n^2+144n^3-48n^4-52n^6-228n^7-24n^8+36n^9+21n^12+60n^13+18n^14-12n^15-12n^18+n^24)/1152,{n,2,15}]
%Y A338950 Cf. A338948 (oriented), A338949 (unoriented), A338951 (achiral), A338954 (edges, faces), A000389 (5-cell), A337954 (8-cell vertices, 16-cell facets), A234249(16-cell vertices, 8-cell facets), A338966 (120-cell, 600-cell).
%K A338950 nonn,easy
%O A338950 2,1
%A A338950 _Robert A. Russell_, Nov 17 2020