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 A077625 #15 Apr 25 2022 08:04:14
%S A077625 0,2,4,6,10,14,22,30,44,62,90,126,180,254,362,510,724,1022,1448,2046,
%T A077625 2896,4094,5792,8190,11584,16382,23170,32766,46340,65534,92680,131070,
%U A077625 185362,262142,370726,524286,741454,1048574,1482910,2097150,2965820,4194302,5931640
%N A077625 Largest term in periodic part of continued fraction expansion of square root of -1+2^n or 0 if -1+2^n is square.
%C A077625 a(n) = 0 iff n = 1, as a consequence of Catalan's conjecture or Mihăilescu's theorem. - _Bernard Schott_, Apr 24 2022
%H A077625 Chai Wah Wu, <a href="/A077625/b077625.txt">Table of n, a(n) for n = 1..80</a>
%H A077625 Wikipedia, <a href="https://en.wikipedia.org/wiki/Catalan's_conjecture">Catalan's conjecture</a>.
%t A077625 Table[Max[Last[ContinuedFraction[Sqrt[ -1+2^u]]]], {u, 1, 32}]
%Y A077625 Cf. A077624-A077635.
%K A077625 nonn
%O A077625 1,2
%A A077625 _Labos Elemer_, Nov 13 2002
%E A077625 Definition clarified, a(1) corrected and a(33)-a(43) added by _Chai Wah Wu_, Apr 19 2022