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