Positions of even numbers in A003136.

Terms

a(0) =1a(1) =4a(2) =7a(3) =9a(4) =14a(5) =16a(6) =20a(7) =22a(8) =26a(9) =30a(10) =33a(11) =37a(12) =39a(13) =42a(14) =45a(15) =50a(16) =52a(17) =54a(18) =59a(19) =64a(20) =66a(21) =69a(22) =75a(23) =80a(24) =82a(25) =83a(26) =85a(27) =93a(28) =94a(29) =96