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 A139766 #10 Sep 16 2015 13:14:45 %S A139766 3,15,104,164,255,2625,2834,11715,18315,48704,49215,64004,65535,73124, %T A139766 131144,215775,491535,525986,546272,568815,952575,1925564,5781434, %U A139766 5861583,13496384,14409548,17646615,17949434,20171384,21475124,22632285 %N A139766 A number n is included in the sequence if and only if the n-th integer from among those positive integers which are coprime to n+1 = the (n+1)-st integer from among those positive integers which are coprime to n. %C A139766 So far it appears that this is a proper subset of A001274. %F A139766 Indices n such that A126356(n) = A126357(n). - _Ray Chandler_ %Y A139766 Cf. A001274, A069213, A126356, A126357. %K A139766 nonn %O A139766 1,1 %A A139766 _Leroy Quet_, Nov 07 2007 %E A139766 More terms from Stefan Steinerberger, Nov 07 2007 %E A139766 a(8) onwards from _Ray Chandler_, Jul 01 2009