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 A086802 #6 Oct 01 2013 17:57:42 %S A086802 0,1,0,2,1,0,4,3,2,0,5,4,3,1,0,7,6,5,3,2,0,8,7,6,4,3,1,0,10,9,8,6,5,3, %T A086802 2,0,13,12,11,9,8,6,5,3,0,14,13,12,10,9,7,6,4,1,0,17,16,15,13,12,10,9, %U A086802 7,4,3,0,19,18,17,15,14,12,11,9,6,5,2,0,20,19,18,16,15,13,12,10,7,6,3,1,0 %N A086802 Triangle read by rows in which row n lists (prime(n)-prime(k))/2 for 2 <= k <= n. %F A086802 (3-3)/2=0; (5-3)/2=1; (5-5)/2=0; (7-3)/2=2; (7-5)/2=1; (7-7)/2=0 %e A086802 0; %e A086802 1, 0; %e A086802 2, 1, 0; %e A086802 4, 3, 2, 0; %e A086802 5, 4, 3, 1, 0; %e A086802 7, 6, 5, 3, 2, 0; %e A086802 8, 7, 6, 4, 3, 1, 0; %e A086802 10, 9, 8, 6, 5, 3, 2, 0 %o A086802 (PARI) fn2(n) = forprime(x=3,n, forprime(y=3,x,print1((x-y)/2","))) %K A086802 easy,tabl,nonn %O A086802 2,4 %A A086802 _Cino Hilliard_, Aug 05 2003