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Search: id:A131976
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| A131976 |
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Let G be the full icosahedral group, of order 120. Let v_1, ..., v_20 be the vertices of the dodecahedron. Let S(n) be the set of vectors v_{i_1} + v_{i_2} + ... + v_{i_n} where 1 <= i_1 <= i_2 <= ... <= i_n <= 20. Then a(n) = number of orbits of G on S(n). |
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2
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| 1, 1, 5, 12, 22, 34, 50, 65, 78, 78, 86, 78, 78, 65, 50, 34, 22, 12, 5, 1, 1
(list; graph; listen)
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OFFSET
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0,3
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LINKS
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Wouter Meeussen, Excel spreadsheet
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EXAMPLE
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For 2 vertices, there are 5 different sets:
{10 pairs with norm^2 of sum = 0.000}
{30 pairs with 1.000}
{60, 2.618}
{60, 5.236}
{30, 6.854}
the norm^2 is taken with the side of the pentagons = 1.
And of course 10+30+60+60+30 = 190 = 20 choose 2
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CROSSREFS
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Sequence in context: A097984 A028347 A038794 this_sequence A074376 A134340 A000326
Adjacent sequences: A131973 A131974 A131975 this_sequence A131977 A131978 A131979
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KEYWORD
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nonn,fini,full
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Oct 06 2007, based on an email message from Wouter Meeussen (wouter.meeussen(AT)pandora.be) on Dec 27 2004.
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EXTENSIONS
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More terms from Wouter Meeussen (wouter.meeussen(AT)pandora.be), Oct 07 2007
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