a(n) = n! * Laguerre(n, 3*n, -n).A295407a(n) = n! * Laguerre(n, 3*n, -n).Terms a(0) =1a(1) =5a(2) =92a(3) =2859a(4) =124832a(5) =7018105a(6) =482598720a(7) =39236322839External referencesoeis: A295407