a(n) is the least square with n binary digits.

Terms

a(0) =4a(1) =9a(2) =16a(3) =36a(4) =64a(5) =144a(6) =256a(7) =529a(8) =1024a(9) =2116a(10) =4096a(11) =8281a(12) =16384a(13) =33124a(14) =65536a(15) =131769a(16) =262144a(17) =525625a(18) =1048576a(19) =2099601a(20) =4194304a(21) =8392609a(22) =16777216a(23) =33558849a(24) =67108864a(25) =134235396a(26) =268435456a(27) =536895241a(28) =1073741824a(29) =2147488281