a(n) = binomial(9*n,n)*(7*n+1)/(8*n+1).

A215553

a(n) = binomial(9*n,n)*(7*n+1)/(8*n+1).

Terms

    a(0) =1a(1) =8a(2) =135a(3) =2574a(4) =51765a(5) =1072764a(6) =22664655a(7) =485325150a(8) =10495906641a(9) =228723580800

External references