Number of 2's in n-th "Kolakoski" string defined in A054349.

Terms

a(0) =1a(1) =2a(2) =2a(3) =3a(4) =5a(5) =8a(6) =11a(7) =16a(8) =25a(9) =38a(10) =57a(11) =85a(12) =127a(13) =192a(14) =289a(15) =430a(16) =644a(17) =966a(18) =1450a(19) =2173a(20) =3263a(21) =4899a(22) =7341a(23) =11022a(24) =16526a(25) =24802a(26) =37201a(27) =55808a(28) =83702a(29) =125541