Column 3 of triangle A152400.

Terms

a(0) =1a(1) =4a(2) =24a(3) =182a(4) =1636a(5) =16844a(6) =194384a(7) =2476868a(8) =34461956a(9) =519070980a(10) =8405444924a(11) =145502477888