a(2n) = A001653(n) (Numbers n such that 2*n^2 - 1 is a square), a(2n+1) = A038725(n+1).

Terms

a(0) =1a(1) =2a(2) =5a(3) =11a(4) =29a(5) =64a(6) =169a(7) =373a(8) =985a(9) =2174a(10) =5741a(11) =12671a(12) =33461a(13) =73852a(14) =195025a(15) =430441a(16) =1136689a(17) =2508794a(18) =6625109a(19) =14622323a(20) =38613965a(21) =85225144a(22) =225058681a(23) =496728541a(24) =1311738121a(25) =2895146102a(26) =7645370045a(27) =16874148071a(28) =44560482149