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 A173400 #4 Jul 12 2012 00:39:51 %S A173400 1,3,7,20,26,33,43,49,52,81,116,140,176,265,288,313,320,323,373,377, %T A173400 395,398,405,408,486,492,530,555,567,592,671,681,772,805,849,874,884, %U A173400 931,936,1016,1030,1149,1204,1324,1347,1406,1464,1550,1621,1639,1707,1712 %N A173400 n-th difference between consecutive primes=n-th difference between consecutive nonnegative nonprimes. %C A173400 Numbers n such that A001223(n)=A054546(n). %F A173400 A001223(a(n))=A054546(a(n)). %Y A173400 Cf. A001223, A075526, A173390, A173401, A029707. %K A173400 nonn,easy,less %O A173400 1,2 %A A173400 _Juri-Stepan Gerasimov_, Feb 17 2010 %E A173400 Extended by _Charles R Greathouse IV_, Mar 25 2010