Number of 2's in row n of the Kolakoski fan A143477.

Terms

a(0) =0a(1) =1a(2) =2a(3) =2a(4) =3a(5) =4a(6) =6a(7) =10a(8) =15a(9) =22a(10) =33a(11) =52a(12) =74a(13) =113a(14) =168a(15) =255a(16) =377a(17) =567a(18) =850a(19) =1280a(20) =1916a(21) =2878a(22) =4324a(23) =6473a(24) =9720a(25) =14577a(26) =21862a(27) =32766a(28) =49150a(29) =73758