Number of ternary trees (A001764) with n nodes and maximal diameter.

Terms

a(0) =1a(1) =3a(2) =12a(3) =45a(4) =162a(5) =567a(6) =1944a(7) =6561a(8) =21870a(9) =72171a(10) =236196a(11) =767637a(12) =2480058a(13) =7971615a(14) =25509168a(15) =81310473a(16) =258280326a(17) =817887699a(18) =2582803260a(19) =8135830269a(20) =25569752274a(21) =80196041223a(22) =251048476872a(23) =784526490225