a(n) = A033001(n)/4.

Terms

a(0) =1a(1) =2a(2) =9a(3) =11a(4) =18a(5) =19a(6) =82a(7) =83a(8) =99a(9) =100a(10) =163a(11) =164a(12) =171a(13) =173a(14) =738a(15) =740a(16) =747a(17) =748a(18) =892a(19) =893a(20) =900a(21) =902a(22) =1467a(23) =1469a(24) =1476a(25) =1477a(26) =1540a(27) =1541a(28) =1557a(29) =1558