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 A077629 #12 Apr 20 2022 18:47:38
%S A077629 0,3,7,7,25,15,63,31,125,63,187,127,1081,255,1091,511,1247,1023,11217,
%T A077629 2047,11999,4095,20259,8191,66077,16383,88609,32767,55491,65535,
%U A077629 284231,131071,413199,262143,585102,524287,3351311,1048575,3462843,2097151
%N A077629 Sum of terms in periodic part of continued fraction expansion of square root of -1+2^n.
%H A077629 Chai Wah Wu, <a href="/A077629/b077629.txt">Table of n, a(n) for n = 1..80</a>
%F A077629 a(2*n) = 2^(n+1) - 1. - _Max Alekseyev_, May 13 2010
%t A077629 Table[Apply[Plus, Last[ContinuedFraction[Sqrt[ -1+2^u]]]], {u, 1, 25}]
%Y A077629 Cf. A077624-A077635.
%K A077629 nonn
%O A077629 1,2
%A A077629 _Labos Elemer_, Nov 13 2002
%E A077629 a(1) corrected, a(26) and on added by _Max Alekseyev_, May 13 2010