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 A173928 #3 Mar 30 2012 18:52:39 %S A173928 0,1,1,7,13,19,19,17,31,5,47,53,47,61,41,67,1,31,47,113,103,79,113,27, %T A173928 73,149,155,57,139,21,37,161,227,211,211,1,337,245,41,117,413,241,337, %U A173928 13,79,451,421,47,181,511,311,323,423,299,545,269,565,211 %N A173928 a(n+2)=A162488(n)-A162489(n) where a(1)=0 and a(2)=1. %C A173928 Where A162488 are numbers x such that x^y+y^x is prime, for some y>1, y<x and A162489 is least y such that x^y+y^x is prime, for x=A162488(n). %e A173928 a(1)=0 because 1^1+1^1=2=prime and 0=1-1; a(2)=1 because 1^2+2^1=3=prime and 1=2-1; a(3)=1 because 2^3+3^2 and 1=3-2; a(4)=7 because 2^9+9^2 and 7=9-2. %Y A173928 Cf. A094133, A162488, A162489. %K A173928 nonn %O A173928 1,4 %A A173928 _Juri-Stepan Gerasimov_, Mar 02 2010 %E A173928 a(30) and a(32) corrected by _R. J. Mathar_, Mar 09 2010