Number of positive words of length n in the monoid Br_8 of positive braids on 9 strands.

A097555

Number of positive words of length n in the monoid Br_8 of positive braids on 9 strands.

Terms

    a(0) =1a(1) =8a(2) =45a(3) =205a(4) =831a(5) =3133a(6) =11294a(7) =39585a(8) =136302a(9) =464026a(10) =1568151a(11) =5273999a(12) =17681042a(13) =59149925a(14) =197598856a(15) =659479754a(16) =2199585548a(17) =7333198205a(18) =24441067317a(19) =81444567492a(20) =271360676916a(21) =904051477063

External references