Number of positive integers <= 2^n of form x^2 + 17 y^2.

Terms

a(0) =1a(1) =1a(2) =2a(3) =2a(4) =4a(5) =9a(6) =15a(7) =28a(8) =53a(9) =100a(10) =184a(11) =342a(12) =656a(13) =1243a(14) =2381a(15) =4579a(16) =8827a(17) =17073a(18) =33108a(19) =64330a(20) =125224a(21) =244171a(22) =476748a(23) =932093a(24) =1824397a(25) =3574605a(26) =7010170a(27) =13759682a(28) =27027854a(29) =53128077