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

A137747

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

Terms

    a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =1a(8) =7a(9) =34a(10) =143a(11) =555a(12) =2050a(13) =7343a(14) =25809a(15) =89642a(16) =308986a(17) =1059786a(18) =3623524a(19) =12365973a(20) =42160774a(21) =143701920a(22) =489891138a(23) =1670965268a(24) =5703849531a(25) =19488123707a(26) =66652727622a(27) =228212500386a(28) =782258463295

External references