A178692 - OEIS

A178692

Expansion of the polynomial (1+x^3)*(1+x^5)*(1+x^7)*(1+x^9)*(1+x^11)*(1+x^13)*(1+x^15).

1, 0, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 2, 1, 2, 2, 3, 1, 3, 2, 3, 3, 2, 4, 3, 4, 2, 5, 3, 4, 3, 4, 4, 3, 4, 3, 5, 2, 4, 3, 4, 2, 3, 3, 2, 3, 1, 3, 2, 2, 1, 2, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 0, 1

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OFFSET

0,13

COMMENTS

This is the Poincaré polynomial for the Lie group A_7.

REFERENCES

Borel, A. and Chevalley, C., The Betti numbers of the exceptional groups, Mem. Amer. Math. Soc. 1955, no. 14, pp 1-9.

LINKS

Table of n, a(n) for n=0..63.

MATHEMATICA

CoefficientList[Expand[Times@@(1+x^Range[3, 15, 2])], x] (* Harvey P. Dale, Jun 11 2018 *)

CROSSREFS

A row of A142724.

Sequence in context: A333860 A277314 A120562 * A364144 A033666 A281511

Adjacent sequences: A178689 A178690 A178691 * A178693 A178694 A178695

KEYWORD

nonn,fini,full

AUTHOR

N. J. A. Sloane, Dec 25 2010

STATUS

approved