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 A337961 Number of chiral pairs of colorings of the 12 pentagonal faces of a regular dodecahedron or the 12 vertices of a regular icosahedron using n or fewer colors. 4
 0, 14, 3720, 132184, 1987720, 17935806, 114638048, 570597216, 2348263008, 8320953630, 26126986952, 74247445272, 194049316552, 472265688622, 1080900468480, 2345089916288, 4854316187136, 9638888023278, 18442173583176 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Each member of a chiral pair is a reflection, but not a rotation, of the other. The SchlĂ¤fli symbols for the regular icosahedron and regular dodecahedron are {3,5} and {5,3} respectively. They are mutually dual. LINKS FORMULA a(n) = (n-1) * n^2 * (n+1) * (n^8 + n^6 - 14*n^4 + 44) / 120. a(n) = 14*C(n,2) + 3678*C(n,3) + 117388*C(n,4) + 1363860*C(n,5) + 7918056*C(n,6) + 26332992*C(n,7) + 53428032*C(n,8) + 67359600*C(n,9) + 51559200*C(n,10) + 21954240*C(n,11) + 3991680*C(n,12), where the coefficient of C(n,k) is the number of chiral pairs of colorings using exactly k colors. a(n) = A000545(n) - A252705(n) = (A000545(n) - A337962(n)) / 2 = A252705(n) - A337962(n). MATHEMATICA Table[(n^12-15n^8+14n^6+44n^4-44n^2)/120, {n, 30}] CROSSREFS Cf. A000545 (oriented), A252705 (unoriented), A337962 (achiral). Other elements: A337959 (dodecahedron vertices, icosahedron faces), A337964 (edges). Other polyhedra: A000332 (tetrahedron), A093566(n+1) (cube faces, octahedron vertices), A337896 (octahedron faces, cube vertices). Sequence in context: A206627 A268179 A268002 * A188955 A157824 A180588 Adjacent sequences:  A337958 A337959 A337960 * A337962 A337963 A337964 KEYWORD nonn,easy AUTHOR Robert A. Russell, Oct 03 2020 STATUS approved

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Last modified May 20 23:05 EDT 2022. Contains 353886 sequences. (Running on oeis4.)