Number of 4-ary rooted trees with n nodes and height at most 6.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =9a(6) =19a(7) =44a(8) =99a(9) =226a(10) =506a(11) =1133a(12) =2506a(13) =5530a(14) =12104a(15) =26408a(16) =57296a(17) =123892a(18) =266712a(19) =572308a(20) =1223488a(21) =2607429a(22) =5538518a(23) =11729577a(24) =24766121a(25) =52143714a(26) =109475193a(27) =229218555a(28) =478646764a(29) =996885485