a(n) = number of strings of length n that can be obtained by starting with abc and repeatedly doubling any substring of length >= 2 in place.

A135156

a(n) = number of strings of length n that can be obtained by starting with abc and repeatedly doubling any substring of length >= 2 in place.

Terms

    a(0) =1a(1) =0a(2) =2a(3) =0a(4) =3a(5) =1a(6) =4a(7) =0a(8) =5a(9) =2a(10) =6a(11) =1a(12) =7a(13) =3a(14) =8a(15) =9a(16) =9a(17) =7a(18) =10a(19) =34a(20) =11a(21) =36a(22) =12a(23) =136a(24) =13a(25) =190a(26) =14a(27) =567a(28) =15a(29) =1018

External references