Number of letters in n (in Russian).

Terms

a(0) =4a(1) =3a(2) =3a(3) =6a(4) =4a(5) =5a(6) =4a(7) =6a(8) =6a(9) =6a(10) =11a(11) =10a(12) =10a(13) =12a(14) =10a(15) =11a(16) =10a(17) =12a(18) =12a(19) =8a(20) =12a(21) =11a(22) =11a(23) =14a(24) =12a(25) =13a(26) =12a(27) =14a(28) =14a(29) =8