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 A167887 #4 Mar 30 2012 18:52:35 %S A167887 2,5,9,17,25,31,39,47,53,60,67,75,83,89,98,103,110,119,126,133,139, %T A167887 154,159,167,181,189,196,201,208,216,230,237,251,264,271,277,285,297, %U A167887 305,312,320,328,334,347,362,368,374,389,396,409,415,422,431,438,445,451 %N A167887 n-th single or isolated number plus n-th non-single or nonisolated number. %F A167887 a(n)=A167706(n)+A167707(n). %e A167887 a(1)=2+0=2, a(2)=4+1=5, a(3)=6+3=9, a(4)=12+5=17. %Y A167887 Cf. A167706, A167707. %K A167887 nonn %O A167887 1,1 %A A167887 _Juri-Stepan Gerasimov_, Nov 14 2009 %E A167887 All terms > 110 corrected by _R. J. Mathar_, May 30 2010