a(n) = Sum_{k=0..n} |Stirling1(n,k)*Stirling2(n,k)|.

A047793

a(n) = Sum_{k=0..n} |Stirling1(n,k)*Stirling2(n,k)|.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =12a(4) =120a(5) =1750a(6) =34615a(7) =882868a(8) =28008694a(9) =1076404824a(10) =49100939538

External references