%N Number of 6-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>
%A _N. J. A. Sloane_.