A005304 Representation degeneracies for Ramond strings. (Formerly M0336)

2, 2, 4, 10, 18, 32, 58, 98, 164, 274, 442, 704, 1114, 1730, 2660, 4058, 6114, 9136, 13554, 19930

Offset

1,1

References

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=1..20.

T. L. Curtright and C. B. Thorn, Symmetry patterns in the mass spectra of dual string models, Nuclear Phys. B 274 (1986), 520-588, Table 6d.

Formula

G.f.: 2 * Product (1 - x^k)^(-c(k)); c(k) = 1, 1, 3, 3, 4, 3, 4, 2, 4, 2, 4, 2, ... [Corrected by Sean A. Irvine, Sep 12 2017. But how does this sequence continue?] Answer: See the generating functions given in Section 5 of Curtright-Thorn. - N. J. A. Sloane, Sep 13 2017

Crossrefs

Sequence in context: A216695 A320069 A002082 * A152732 A308986 A100088

Adjacent sequences: A005301 A005302 A005303 * A005305 A005306 A005307

Keyword

nonn,more

Author

N. J. A. Sloane.

Status

approved