%I #13 Dec 23 2020 04:36:21

%S 0,0,0,1,2,4,6,8,9,11,11,12,11,11,9,8,6,5,3,2,1,1

%N Number of 4-ary rooted trees with n nodes and height exactly 3.

%H E. M. Rains and N. J. A. Sloane, <a href="https://cs.uwaterloo.ca/journals/JIS/cayley.html">On Cayley's Enumeration of Alkanes (or 4-Valent Trees)</a>, J. Integer Sequences, Vol. 2 (1999), Article 99.1.1.

%H <a href="/index/Ro#rooted">Index entries for sequences related to rooted trees</a>

%K nonn,fini,full

%O 0,5

%A _N. J. A. Sloane_.