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 A247094 #19 Nov 28 2014 22:46:04 %S A247094 1,2,3,5,27,565,7085,48771,1266205,9099507,17602325,128207979, %T A247094 26494256091,11147523830125,84179432287299,165269711096165, %U A247094 281629680514649643,4246732448623781667,126774939137440139965,1925041114036033717685,14833445639443302757131 %N A247094 Integers of the form (2^k + 1)/(2k + 1). %C A247094 a(A103579(n)) is a subsequence. %C A247094 Numbers n such that 2n + 1 divides 2^n + 1: 0, 1, 2, 5, 6, 9, 14, 18, 21, 26, 29, 30, 33, 41, 50, 53, ... %H A247094 Colin Barker, <a href="/A247094/b247094.txt">Table of n, a(n) for n = 1..400</a> %e A247094 1 is in this sequence because (2^1 + 1)/(2*1 + 1) = 1, %e A247094 2 is in this sequence because (2^0 + 1)/(2*0 + 1) = 2, %e A247094 3 is in this sequence because (2^5 + 1)/(2*5 + 1) = 3. %o A247094 (PARI) s=[]; for(k=0, 100, t=(2^k + 1)/(2*k + 1); if(type(t)=="t_INT", s=concat(s, t))); s=vecsort(s,,8) \\ _Colin Barker_, Nov 18 2014 %Y A247094 Cf. A081856, A081858, A103579, A224486, A247132. %K A247094 nonn %O A247094 1,2 %A A247094 _Juri-Stepan Gerasimov_, Nov 18 2014 %E A247094 a(19) corrected by _Colin Barker_, Nov 18 2014