A104593 Number of labeled planar 2-connected graphs with no vertex of degree 2 and with n vertices.

1, 25, 1317, 96012, 8976600, 1027205280, 139315157730, 21864486188160, 3898841480307900, 778680435365714700, 172192746831203449890, 41765231538761743574100, 11024455369912310561835600

Offset

4,2

Comments

By empirical evidence, the terms possess a curious prime factor behavior. E.g. 2^4*3^4*5^2*7*11*13^2 divides a(16)=11024455369912310561835600.

Links

A. Gagarin et al., Table of n, a(n) for n = 4..20

A. Gagarin, G. Labelle and P. Leroux, Counting labeled projective-planar graphs without a K_{3,3}-subdivision, arXiv:math/0406140 [math.CO], 2004-2006.

Crossrefs

Cf. A104592.

Sequence in context: A174751 A042203 A042200 * A046910 A278851 A243943

Adjacent sequences: A104590 A104591 A104592 * A104594 A104595 A104596

Keyword

nonn

Author

Valery A. Liskovets, Mar 22 2005

Status

approved