OFFSET
0,3
COMMENTS
The term a(0)=1 can be interpreted as either a singleton vertex or the graph with no vertices. - Andrew Howroyd, Jan 14 2022
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..40
PROG
(PARI) \\ See PARI link in A350489 for program code.
A139627seq(20) \\ Andrew Howroyd, Jan 14 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Jubin, May 01 2008
EXTENSIONS
3 more terms from R. J. Mathar, Aug 04 2017
Terms a(7) and beyond from Andrew Howroyd, Jan 14 2022
STATUS
approved