a(n) = A000930(n*(n+1)/2), where A000930 is Narayana's cows sequence.

A231621

a(n) = A000930(n*(n+1)/2), where A000930 is Narayana's cows sequence.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =28a(5) =189a(6) =1873a(7) =27201a(8) =578949a(9) =18059374a(10) =825604416a(11) =55315679788

External references