OFFSET
0,14
LINKS
E. M. Rains and N. J. A. Sloane, On Cayley's Enumeration of Alkanes (or 4-Valent Trees), J. Integer Sequences, Vol. 2 (1999), Article 99.1.1.
EXAMPLE
Triangle begins:
1;
1,1;
1,1,1,1,1,1,1;
1,1,1,2,...
CROSSREFS
KEYWORD
nonn,tabf,easy
AUTHOR
STATUS
approved