a(n) = (1/2)*(s(n) + 1), where s(n) is the n-th odd number in A002251.

Terms

a(0) =1a(1) =3a(2) =4a(3) =2a(4) =7a(5) =8a(6) =12a(7) =5a(8) =6a(9) =16a(10) =20a(11) =21a(12) =9a(13) =24a(14) =25a(15) =10a(16) =11a(17) =29a(18) =33a(19) =13a(20) =14a(21) =37a(22) =38a(23) =15a(24) =41a(25) =42a(26) =17a(27) =45a(28) =46a(29) =18