A136417 Number of squares <= 2^n.

2, 2, 3, 3, 5, 6, 9, 12, 17, 23, 33, 46, 65, 91, 129, 182, 257, 363, 513, 725, 1025, 1449, 2049, 2897, 4097, 5793, 8193, 11586, 16385, 23171, 32769, 46341, 65537, 92682, 131073, 185364, 262145, 370728, 524289, 741456, 1048577, 1482911, 2097153

Offset: 0

Author

Giovanni Teofilatto, Apr 01 2008

Keywords

• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A000079.

Programs

Magma

[1+Floor(Sqrt(2^n)): n in [0..45]]; // Vincenzo Librandi, Aug 06 2014

Mathematica

1 + Floor[(Sqrt[2])^Range[0, 50]] (* Vincenzo Librandi, Aug 06 2014 *)

PARI

a(n) = for(k=0,2^(n+1),if(k^2 > 2^n, return(k)))
vector(50, n, a(n-1)) \\ Derek Orr, Aug 05 2014

Formula

a(n) = 1 + A017910(n). - R. J. Mathar, Apr 04 2008

Extensions

More terms from R. J. Mathar, Apr 04 2008