a(n) = 2*A094555(n).

Terms

a(0) =0a(1) =2a(2) =2a(3) =12a(4) =22a(5) =92a(6) =222a(7) =772a(8) =2102a(9) =6732a(10) =19342a(11) =59732a(12) =175782a(13) =534172a(14) =1588862a(15) =4793892a(16) =14327062a(17) =43090412a(18) =129052782a(19) =387595252a(20) =1161911942a(21) =3487483452a(22) =10458955102a(23) =31383855812a(24) =94137586422a(25) =282440721292a(26) =847266239822