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A089011 a(n) = 1 if n is an exponent of the Weyl group W(E_7), 0 otherwise. 4
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; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

Index entries for characteristic functions

FORMULA

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)).

PROG

(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 */

CROSSREFS

Cf. A005763, A089010.

Sequence in context: A141728 A141737 A285301 * A267043 A266444 A267679

Adjacent sequences:  A089008 A089009 A089010 * A089012 A089013 A089014

KEYWORD

easy,nonn

AUTHOR

Paul Boddington, Nov 03 2003

STATUS

approved

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Last modified February 17 18:14 EST 2020. Contains 332005 sequences. (Running on oeis4.)