a(0) = 1; a(n) = (n!)^2 * Sum_{k=0..n-1} a(k) / (k! * (n-k))^2.

A336258

a(0) = 1; a(n) = (n!)^2 * Sum_{k=0..n-1} a(k) / (k! * (n-k))^2.

Terms

    a(0) =1a(1) =1a(2) =5a(3) =58a(4) =1208a(5) =39476a(6) =1861372a(7) =119587224a(8) =10040970816

External references