OFFSET
0,4
COMMENTS
The values 1,5,35,319,... also are the number of Feynman diagrams of the Green's function of 2,4,6,8,... vertices which have no tadpoles (i.e. no edges that connect a vertex to itself), a subset of the graphs in A000698, vixra:1901.0148. This is likely a random coincidence. - R. J. Mathar, Mar 07 2022
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 0..124
FORMULA
EXAMPLE
CROSSREFS
KEYWORD
sign
AUTHOR
Vaclav Kotesovec, Aug 05 2015
STATUS
approved