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 A247798 #4 Sep 26 2014 13:26:27 %S A247798 1,2,3,4,7,6,7,14,9,10,19,12,16,20,15,16,28,26,19,32,21,22,43,24,29, %T A247798 41,27,38,46,30,31,55,44,34,55,36,37,71,50,40,61,42,57,68,45,58,73,63, %U A247798 49,82,51,52,116,54,55,86,57,76,95,74,67,95,78,64,100,66 %N A247798 n-th positive integer relatively prime to 2*n - 1. %C A247798 Central terms of triangle A077581. %H A247798 Reinhard Zumkeller, <a href="/A247798/b247798.txt">Table of n, a(n) for n = 1..1000</a> %o A247798 (Haskell) %o A247798 a247798 n = a077581 (2 * n - 1) n %Y A247798 Cf. A077581, A069213. %K A247798 nonn %O A247798 1,2 %A A247798 _Reinhard Zumkeller_, Sep 26 2014