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 A084578 #3 Mar 30 2012 18:36:34 %S A084578 1,3,6,8,13,15,18,20,22,25,27,30,34,37,39,46,51,54,56,59,61,63,66,71, %T A084578 78,80,87,90,92,95,97,102,104,109,112,114,119,121,124,126,131,133,136, %U A084578 138,140,143,145,148,157,160,162,165,174,179,181,184,189,191,208,210,213 %N A084578 Positive integers not found in A084577. %Y A084578 Cf. A084576, A084577, A084579-A084587. %K A084578 nonn %O A084578 1,2 %A A084578 _Paul D. Hanna_, May 31 2003