Number of squares <= 2^n.

Terms

a(0) =2a(1) =2a(2) =3a(3) =3a(4) =5a(5) =6a(6) =9a(7) =12a(8) =17a(9) =23a(10) =33a(11) =46a(12) =65a(13) =91a(14) =129a(15) =182a(16) =257a(17) =363a(18) =513a(19) =725a(20) =1025a(21) =1449a(22) =2049a(23) =2897a(24) =4097a(25) =5793a(26) =8193a(27) =11586a(28) =16385a(29) =23171