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 A014121 #41 Jun 19 2025 12:15:03
%S A014121 0,1,2,3,5,7,8,11,13,15,17,19,23,25,26,29,31,37,47,49,55,61,63,65,73,
%T A014121 77,79,80,101,115,119,125,127,139,175,179,211,217,227,229,235,239,241,
%U A014121 242,247,253,255,269,295,431,473,485,503,509,511,601,665,697,713,721,725,727,728,781,943,997
%N A014121 Numbers of form |2^i - 3^j|.
%C A014121 A128760(a(n)) > 0. - _Reinhard Zumkeller_, Mar 25 2007
%C A014121 One can establish if a given integer m is a term by computing all integral points on elliptic curves u*x^3 - v*y^2 = +-m for all u in {1,2,4} and v in {1, 3} and identifying if for any point x is a power of 2 while y is a power of 3. - _Max Alekseyev_, Jun 17 2025
%H A014121 Kevin Ryde, <a href="/A014121/a014121.txt">Conjectured table of n, a(n) for n = 1..3000</a>
%H A014121 Kevin Ryde, <a href="/A014121/a014121.gp.txt">PARI/GP Code</a>
%H A014121 Terence Tao, <a href="https://terrytao.wordpress.com/2011/08/21/hilberts-seventh-problem-and-powers-of-2-and-3/">Hilbert's seventh problem, and powers of 2 and 3</a>
%H A014121 Ralf Stephan, <a href="/A014121/a014121_1.gp.txt">PARI/GP code to check for absent values</a>.
%o A014121 (PARI) \\ See links.
%K A014121 nonn
%O A014121 1,3
%A A014121 Richard C. Schroeppel
%E A014121 More terms from _Max Alekseyev_, Nov 16 2012