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 A051220 #9 May 14 2017 22:48:34
%S A051220 0,1,5,8,9,17,32,45,53,56,65,72,77,80,81,104,153,161,200,245,288,320,
%T A051220 329,368,405,440,473,477,485,504,533,560,585,608,629,632,648,665,680,
%U A051220 693,704,713,720,725,728,729,785,936,968,1085,1232,1377,1449,1457,1520
%N A051220 Numbers of the form 9^x-y^2 >= 0.
%t A051220 max = 2000; Clear[f]; f[m_] := f[m] = Select[Table[9^x - y^2, {x, 0, m}, {y, 0, Ceiling[9^(x/2)]}] // Flatten // Union, 0 <= # <= max &]; f[1]; f[m = 2]; While[f[m] != f[m - 1], m++]; Print["m = ", m]; A051219 = f[m] (* _Jean-François Alcover_, May 14 2017 *)
%K A051220 nonn
%O A051220 1,3
%A A051220 _David W. Wilson_