a(n) = Sum_{k=0..2*n} Stirling1(2*n+1, 2*n+1-k) * Stirling1(2*n+1, k+1).

A384028

a(n) = Sum_{k=0..2*n} Stirling1(2*n+1, 2*n+1-k) * Stirling1(2*n+1, k+1).

Terms

    a(0) =1a(1) =13a(2) =2273a(3) =1184153a(4) =1251320145

External references