A051206 Numbers of the form x^2-4^y >= 0.

0, 3, 5, 8, 9, 12, 15, 17, 20, 21, 24, 32, 33, 35, 36, 45, 48, 57, 60, 63, 65, 68, 77, 80, 84, 96, 99, 105, 117, 120, 128, 129, 132, 140, 143, 144, 153, 161, 165, 168, 180, 185, 192, 195, 201, 209, 221, 224, 225, 228, 240, 252, 255, 257, 260, 272, 273, 285, 288, 297

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Programs

Mathematica

max = 300; Clear[f]; f[m_] := f[m] = Select[Table[x^2 - 4^y, {y, 0, m}, {x, Floor[4^(y/2)], Ceiling[Sqrt[4^y + max]]}] // Flatten // Union, 0 <= # <= max &]; f[1]; f[m = 2]; While[f[m] != f[m - 1], m++]; Print["m = ", m]; A051206 = f[m] (* Jean-François Alcover, May 14 2017 *)