Even numbers to the left of the central elements of the (1,2)-Pascal triangle A029635.

Terms

a(0) =4a(1) =6a(2) =14a(3) =20a(4) =8a(5) =50a(6) =10a(7) =44a(8) =112a(9) =182a(10) =54a(11) =156a(12) =294a(13) =12a(14) =210a(15) =450a(16) =672a(17) =660a(18) =1122a(19) =14a(20) =90a(21) =352a(22) =1782a(23) =2508a(24) =104a(25) =442a(26) =4290a(27) =16a(28) =546a(29) =4004