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

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =9a(5) =16a(6) =29a(7) =54a(8) =97a(9) =180a(10) =337a(11) =633a(12) =1197a(13) =2280a(14) =4357a(15) =8363a(16) =16096a(17) =31064a(18) =60108a(19) =116555a(20) =226419a(21) =440616a(22) =858696a(23) =1675603a(24) =3273643a(25) =6402706a(26) =12534812a(27) =24561934a(28) =48168461a(29) =94534626