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 A179676 #9 Mar 30 2012 18:52:59
%S A179676 7,15,21,23,31,35,39,45,47,49,51,55,63,71,73,75,79,85,87,89,91,93,95,
%T A179676 103,105,111,115,117,119,123,127,133,135,143,147,151,153,155,159,161,
%U A179676 165,167,175,183,187,189,191,195,199,215,217,219,221,223,225,231,233,235,237,239,245,247,253,255,259
%N A179676 Numbers m=2*n-1 for all n>2 not in A179460.
%C A179676 Consider the algorithm of calculation ord_(2n-1)(2) in A179680, and the average of the 2-adic orders l_1, ..., l_k defined there. For terms of the sequence it is more than 2, while for other odd numbers(>=3), it equals 2. This means that only for the terms of the sequence the number of odd residues in {1,2,...,2^ord_(2*n-1)(2)} (considered in the reduced residue system modulo 2*n-1)less than even ones.
%Y A179676 Cf. A179460, A007814, A002326
%K A179676 nonn,uned
%O A179676 1,1
%A A179676 _Vladimir Shevelev_, Jul 24 2010