A273723 Number of ternary heaps on n levels (i.e., of (3^n-1)/2 elements).

1, 1, 6, 7484400, 35417271278873496315860673177600000000

Offset: 0

Author

Alois P. Heinz, May 28 2016

Keywords

• nonn

Comments

a(n) is also the number of labeled histories for a fully symmetric trifurcating labeled topology with 3^n leaves. - Noah A Rosenberg, Feb 24 2025

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..6
• E. H. Dickey, N. A. Rosenberg, Labelled histories with multifurcation and simultaneity, Phil. Trans. R. Soc. B 380 (2025), 20230307.
• Wikipedia, D-ary heap

Crossrefs

Column k=3 of A273712.

Cf. A003462, A178008.

Formula

a(n) = A178008(A003462(n)).