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 A207573 #15 May 13 2013 01:50:04 %S A207573 1,2,3,4,7,12,29,84,355,2038,15723,156920,1959177,29788564,539206155, %T A207573 11406258536,277708694711,7683630307352,239005572292955, %U A207573 8281900782667178,317172995786425445 %N A207573 a(1)=1, a(n+1) = prime(a(n)+1) - a(n). %e A207573 a(2) = prime(a(1)+1)-a(1) = 3-1 = 2; %e A207573 a(3) = prime(a(2)+1)-a(2) = 5-2 = 3; %e A207573 a(4) = prime(a(3)+1)-a(3) = 7-3 = 4; %e A207573 a(5) = prime(a(4)+1)-a(4) = 11-4 = 7. %Y A207573 Cf. A006508, A000040. %K A207573 nonn %O A207573 1,2 %A A207573 _Gerasimov Sergey_, Feb 19 2012 %E A207573 a(19)-a(21) from _Charles R Greathouse IV_, Feb 20 2012