2*A007318^(2) - A000012.

Terms

a(0) =1a(1) =3a(2) =1a(3) =7a(4) =7a(5) =1a(6) =15a(7) =23a(8) =11a(9) =1a(10) =31a(11) =63a(12) =47a(13) =15a(14) =1a(15) =63a(16) =159a(17) =159a(18) =79a(19) =19a(20) =1a(21) =127a(22) =383a(23) =479a(24) =319a(25) =119a(26) =23a(27) =1a(28) =255a(29) =895