OFFSET
8,1
COMMENTS
By empirical evidence, the terms possess a curious prime factor behavior. E.g. 2^5*3^3*5^3*7^2*11*13*17*19 divides a(20)=233306923207078035272369412000.
LINKS
A. Gagarin, G. Labelle and P. Leroux, Characterization and enumeration of toroidal K_{3,3}-subdivision-free graphs, arXiv:math/0411356 [math.CO], 2004.
CROSSREFS
KEYWORD
nonn
AUTHOR
Valery A. Liskovets, Mar 22 2005
STATUS
approved