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 A051217 #35 Oct 14 2023 23:44:09
%S A051217 0,1,2,5,6,11,20,27,32,35,36,47,71,72,95,116,135,140,152,167,180,191,
%T A051217 200,207,212,215,216,272,335,380,396,431,455,512,551,567,620,671,720,
%U A051217 767,812,855,860,887,896,935,972,1007,1040,1052,1071,1100,1127,1152
%N A051217 Nonnegative numbers of the form 6^x - y^2.
%C A051217 No integers congruent to {3,4,8,9} mod 10. - _Zak Seidov_, Nov 14 2011
%C A051217 If k is not in this sequence, then A200440 gives the least modulus which proves that there cannot be a solution to k = 6^x - y^2. - _M. F. Hasler_, Nov 18 2011
%H A051217 Hugo Pfoertner, <a href="/A051217/b051217.txt">Table of n, a(n) for n = 1..513</a>
%t A051217 max = 10^5; Clear[f]; f[m_] := f[m] = Select[Table[6^x - y^2, {x, 0, m}, {y, 0, Ceiling[6^(x/2)]}] // Flatten // Union, 0 <= # <= max &]; f[1]; f[m = 2]; While[f[m] != f[m - 1], m++]; Print["m = ", m]; A051217 = f[m] (* _Jean-François Alcover_, May 13 2017 *)
%o A051217 (PARI) is_A051217(n) = !A200440(n) \\ _M. F. Hasler_, Nov 18 2011
%Y A051217 Cf. A201122.
%K A051217 nonn
%O A051217 1,3
%A A051217 _David W. Wilson_