Number of 2's in n-th term of A022470.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =3a(6) =4a(7) =5a(8) =7a(9) =7a(10) =11a(11) =14a(12) =16a(13) =22a(14) =34a(15) =37a(16) =56a(17) =70a(18) =94a(19) =113a(20) =161a(21) =191a(22) =252a(23) =341a(24) =435a(25) =568a(26) =762a(27) =973a(28) =1276a(29) =1661