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 A174870 #4 Mar 30 2012 18:52:53 %S A174870 1,9,21,25,27,33,45,57,75,77,81,85,91,93,105,115,117,121,125,133,135, %T A174870 141,145,147,165,169,171,175,177,187,189,201,205,213,217,221,225,231, %U A174870 235,243,245,247,253,261,273,275,289,297,301,315,325,333,343,345,355,357,361,363 %N A174870 Odd indices m for which A174869(m) is <>1. %C A174870 All but the first term in the sequence are composite numbers. %e A174870 The 9 refers to A174869(9) = 7. The 21 refers to A174869(21) = 3. %Y A174870 Cf. A174869, A006530, A103667, A023503, A023509, A174857, A020639 ,A002618, A036689. %K A174870 nonn %O A174870 1,2 %A A174870 _Vladimir Shevelev_, Mar 31 2010 %E A174870 More terms from _R. J. Mathar_, Aug 10 2010