Number of words of length n over the alphabet {0, ..., n-1} that avoid the pattern 1221.

A239375

Number of words of length n over the alphabet {0, ..., n-1} that avoid the pattern 1221.

Terms

    a(0) =1a(1) =1a(2) =4a(3) =27a(4) =250a(5) =2915a(6) =40766a(7) =662494a(8) =12236190a(9) =252664815a(10) =5759288044a(11) =143463453199

External references