Number of different strings of length n obtained from "abcde" by iteratively duplicating any substring.

A137745

Number of different strings of length n obtained from "abcde" by iteratively duplicating any substring.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =1a(6) =5a(7) =19a(8) =66a(9) =218a(10) =700a(11) =2218a(12) =6997a(13) =22064a(14) =69662a(15) =220395a(16) =699090a(17) =2224114a(18) =7098773a(19) =22733498a(20) =73048903a(21) =235504760a(22) =761689193a(23) =2471105355a(24) =8040439771a(25) =26235143469a(26) =85831045851a(27) =281519068056a(28) =925596771195

External references