a(n) is the smallest centered square number with binary weight n.

Terms

a(0) =1a(1) =5a(2) =13a(3) =85a(4) =61a(5) =221a(6) =761a(7) =1013a(8) =2813a(9) =12013a(10) =23545a(11) =54781a(12) =16381a(13) =196565a(14) =425965a(15) =770041a(16) =3137513a(17) =7663613a(18) =13629421a(19) =20962813a(20) =63946741a(21) =121602013a(22) =192805885a(23) =499122013a(24) =989724541a(25) =2411720701a(26) =6435110905a(27) =17162301181a(28) =29929502461a(29) =63753420281