Number of squarefree words of length n in an n-ary alphabet, with new values 0..n-1 introduced in increasing order.

A215070

Number of squarefree words of length n in an n-ary alphabet, with new values 0..n-1 introduced in increasing order.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =4a(4) =12a(5) =40a(6) =154a(7) =660a(8) =3114a(9) =15930a(10) =87645a(11) =514851a(12) =3211220a(13) =21166029a(14) =146849903a(15) =1068808441a(16) =8136559688a(17) =64621235409a(18) =534207882566

External references