Positions of 2's in A171922.

Terms

a(0) =2a(1) =3a(2) =5a(3) =9a(4) =13a(5) =24a(6) =48a(7) =72a(8) =119a(9) =220a(10) =348a(11) =407a(12) =587a(13) =797a(14) =1125a(15) =1555a(16) =1847a(17) =2581a(18) =3560a(19) =3571a(20) =3690a(21) =4982a(22) =6739a(23) =7134a(24) =9429a(25) =11659