A051216 Numbers of the form 5^x-y^2 >= 0.

0, 1, 4, 5, 9, 16, 21, 24, 25, 44, 49, 61, 76, 89, 96, 100, 109, 116, 121, 124, 125, 141, 184, 209, 225, 249, 264, 284, 301, 316, 336, 369, 400, 421, 429, 456, 481, 496, 504, 524, 525, 544, 561, 576, 589, 600, 609, 616, 621, 624, 625, 724, 741, 821, 841, 916, 984

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Programs

Mathematica

max = 1000; Clear[f]; f[m_] := f[m] = Select[Table[5^x - y^2, {x, 0, m}, {y, 0, Ceiling[5^(x/2)]}] // Flatten // Union, 0 <= # <= max&]; f[1]; f[m = 2]; While[f[m] != f[m-1], m++]; Print["m = ", m]; A051216 = f[m] (* Jean-François Alcover, May 13 2017 *)