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Search: id:A008643
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| A008643 |
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Molien series for group of 4 X 4 upper triangular matrices over GF(2). |
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+0
1
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| 1, 1, 2, 2, 4, 4, 6, 6, 10, 10, 14, 14, 20, 20, 26, 26, 35, 35, 44, 44, 56, 56, 68, 68, 84, 84, 100, 100, 120, 120, 140, 140, 165, 165, 190, 190, 220, 220, 250, 250, 286, 286, 322, 322, 364, 364, 406, 406
(list; graph; listen)
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OFFSET
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0,3
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REFERENCES
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D. J. Benson, Polynomial Invariants of Finite Groups, Cambridge, 1993, p. 105.
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LINKS
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INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 233
Index entries for Molien series
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FORMULA
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G.f.: 1/((1-x)*(1-x^2)*(1-x^4)*(1-x^8)).
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MAPLE
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a:= proc(n) local m, r; m := iquo (n, 8, 'r'); r:= iquo(r, 2)+1; ([11, 17, 26, 35][r]+ (9+ 3*r+ 4*m) *m) *m/3+ [1, 2, 4, 6][r] end: seq (a(n), n=0..100); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Oct 06 2008]
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CROSSREFS
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Sequence in context: A001310 A029009 A023023 this_sequence A008644 A008645 A018819
Adjacent sequences: A008640 A008641 A008642 this_sequence A008644 A008645 A008646
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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