Digits even, nonzero and nondecreasing.

Terms

a(0) =2a(1) =4a(2) =6a(3) =8a(4) =22a(5) =24a(6) =26a(7) =28a(8) =44a(9) =46a(10) =48a(11) =66a(12) =68a(13) =88a(14) =222a(15) =224a(16) =226a(17) =228a(18) =244a(19) =246a(20) =248a(21) =266a(22) =268a(23) =288a(24) =444a(25) =446a(26) =448a(27) =466a(28) =468a(29) =488