A089488 - OEIS

%I #4 Oct 01 2013 17:57:55

%S 3,3,7,3,3,3,3,3,7,3,7,3,3,43,3,7,19,7,3,3,7,3,3,7,19,3,13,3,3,31,13,

%T 3,3,7,3,3,3,3,13,7,7,13,3,7,3,19,3,19,3,7,7,3,7,7,19,19,3,3,13,7,19,

%U 3,19,13,19,7,3,3,3,7,3,13,3,7,3,3,7,19,3,3,13,3,13,19,19,3,13,7,3,3,3,3,3

%N First occurrence where (p-q)/(q-3), p and q are primes.

%o (PARI) \ r is the occurrence desired 1=first,2=second etc. \d is the amount we take from q diff2sqp2(n,r,d) = { forprime(q=d+1,n, c=0; forprime(p=q+1,n, y=(p-q)/(q-d); if(y==floor(y), if(isprime(y),c++; if(c==r, print1(y",");break)) ) ) ) }

%K easy,nonn

%O 5,1

%A _Cino Hilliard_, Dec 28 2003