"BHK" (reversible, identity, unlabeled) transform of 2,2,2,2,...

Terms

a(0) =2a(1) =3a(2) =8a(3) =23a(4) =74a(5) =227a(6) =704a(7) =2135a(8) =6482a(9) =19523a(10) =58808a(11) =176663a(12) =530714a(13) =1592867a(14) =4780784a(15) =14344535a(16) =43040162a(17) =129127043a(18) =387400808a(19) =1162222103a(20) =3486725354a(21) =10460235107a(22) =31380882464a(23) =94142824535a(24) =282429005042