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

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =8a(6) =14a(7) =26a(8) =44a(9) =76a(10) =125a(11) =206a(12) =327a(13) =521a(14) =802a(15) =1231a(16) =1845a(17) =2742a(18) =3987a(19) =5748a(20) =8124a(21) =11364a(22) =15615a(23) =21212a(24) =28336a(25) =37412a(26) =48597a(27) =62368a(28) =78810a(29) =98359