Even numbers written backwards.

Terms

a(0) =0a(1) =2a(2) =4a(3) =6a(4) =8a(5) =1a(6) =21a(7) =41a(8) =61a(9) =81a(10) =2a(11) =22a(12) =42a(13) =62a(14) =82a(15) =3a(16) =23a(17) =43a(18) =63a(19) =83a(20) =4a(21) =24a(22) =44a(23) =64a(24) =84a(25) =5a(26) =25a(27) =45a(28) =65a(29) =85