a(n) = 10/(n + 1) * Catalan(3*n).

A387249

a(n) = 10/(n + 1) * Catalan(3*n).

Terms

    a(0) =10a(1) =25a(2) =440a(3) =12155a(4) =416024a(5) =16158075a(6) =682341000a(7) =30582833775

External references