a(n) = A008277(3*n-1,n) / (n*(n+1)/2) for n>=1, where A008277 are the Stirling numbers of the second kind.
A274712
a(n) = A008277(3*n-1,n) / (n*(n+1)/2) for n>=1, where A008277 are the Stirling numbers of the second kind.
Terms
- a(0) =1a(1) =5a(2) =161a(3) =14575a(4) =2671669a(5) =833607138a(6) =397984073059
External references
- oeis: A274712