A086802 Triangle read by rows in which row n lists (prime(n)-prime(k))/2 for 2 <= k <= n.
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, 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, 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
Offset: 2
Examples
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, 2, 0
Programs
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PARI
fn2(n) = forprime(x=3,n, forprime(y=3,x,print1((x-y)/2",")))
Formula
(3-3)/2=0; (5-3)/2=1; (5-5)/2=0; (7-3)/2=2; (7-5)/2=1; (7-7)/2=0