a(n) = [x^n] Product_{k=1..n} 1/(1-k!*x).A299036a(n) = [x^n] Product_{k=1..n} 1/(1-k!*x).Terms a(0) =1a(1) =1a(2) =7a(3) =381a(4) =502789a(5) =33572762781External referencesoeis: A299036