a(n) = (1/4)*s(n), where s(n) is the n-th multiple of 4 in A026142.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =6a(5) =8a(6) =9a(7) =11a(8) =4a(9) =14a(10) =15a(11) =17a(12) =18a(13) =20a(14) =7a(15) =23a(16) =24a(17) =26a(18) =27a(19) =29a(20) =10a(21) =32a(22) =33a(23) =35a(24) =12a(25) =38a(26) =13a(27) =41a(28) =42a(29) =44