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Search: id:A089011
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| A089011 |
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1 if n is an exponent of the Weyl group W(E_7), 0 otherwise. |
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+0
1
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| 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The exponents are 1, 5, 7, 9, 11, 13, 17. The point of this sequence is that a similar generating function gives the exponents for any finite Coxeter group.
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LINKS
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Index entries for characteristic functions
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FORMULA
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Euler transform of length 14 sequence [ 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, -1, 0, -1]. - Michael Somos Mar 07 2007
G.f.: x*(1-x^12)*(1-x^14)/((1-x^4)*(1-x^6)).
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PROGRAM
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(PARI) {a(n)=if(n<1, 0, polcoeff( x^17+x^13+x^11+x^9+x^7+x^5+x, n))} /* Michael Somos Mar 07 2007 */
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CROSSREFS
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Cf. A005763.
Sequence in context: A141738 A141728 A141737 this_sequence A095111 A166253 A159638
Adjacent sequences: A089008 A089009 A089010 this_sequence A089012 A089013 A089014
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KEYWORD
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easy,nonn
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AUTHOR
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Paul Boddington (psb(AT)maths.warwick.ac.uk), Nov 03 2003
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