"BHK" (reversible, identity, unlabeled) transform of 2,1,1,1,...

Terms

a(0) =2a(1) =2a(2) =5a(3) =14a(4) =39a(5) =107a(6) =289a(7) =772a(8) =2047a(9) =5402a(10) =14213a(11) =37325a(12) =97905a(13) =256622a(14) =672337a(15) =1760998a(16) =4611643a(17) =12075527a(18) =31617521a(19) =82781216a(20) =216732891a(21) =567428402a(22) =1485570025a(23) =3889310329a(24) =10182407329a(25) =26657986682a(26) =69791674109a(27) =182717232062a(28) =478360339887