a(n) = n!*LaguerreL(n, -n^2).A340863a(n) = n!*LaguerreL(n, -n^2).Terms a(0) =1a(1) =2a(2) =34a(3) =1626a(4) =151064a(5) =23046370a(6) =5228520912External referencesoeis: A340863