OFFSET
0,2
COMMENTS
There are no unrooted labeled trees on 4n or 4n+1 or 4n+3 nodes with node degree either one or five.
LINKS
Math.Stackexchange.com, Marko Riedel et al., Number of labeled trees
MAPLE
seq(binomial(4*n+2, n)*(4*n)!/4!^n, n=0..20);
MATHEMATICA
Table[Binomial[4*n+2, n]*(4*n)!/(4!)^n, {n, 0, 10}] (* G. C. Greubel, Jun 09 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Marko Riedel, Jun 09 2016
STATUS
approved