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

A137746

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

Terms

    a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =1a(7) =6a(8) =26a(9) =100a(10) =360a(11) =1246a(12) =4217a(13) =14102a(14) =46861a(15) =155212a(16) =513336a(17) =1697264a(18) =5614670a(19) =18594258a(20) =61671770a(21) =204907302a(22) =682110940a(23) =2275141754a(24) =7603690251a(25) =25462152854a(26) =85428752530a(27) =287163766530a(28) =967046587261

External references