This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A051216 #10 May 13 2017 12:00:52
%S A051216 0,1,4,5,9,16,21,24,25,44,49,61,76,89,96,100,109,116,121,124,125,141,
%T A051216 184,209,225,249,264,284,301,316,336,369,400,421,429,456,481,496,504,
%U A051216 524,525,544,561,576,589,600,609,616,621,624,625,724,741,821,841,916,984
%N A051216 Numbers of the form 5^x-y^2 >= 0.
%t A051216 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 *)
%K A051216 nonn
%O A051216 1,3
%A A051216 _David W. Wilson_