a(n) = 2^C(n+1,2)*A006012(n).A166231a(n) = 2^C(n+1,2)*A006012(n).Terms a(0) =1a(1) =4a(2) =48a(3) =1280a(4) =69632a(5) =7602176a(6) =1660944384a(7) =725849473024External referencesoeis: A166231