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%I #7 Oct 01 2013 21:35:30
%S 2,2,2,17,31,971,127,856073,19427,58537,176123,529393,8191,
%T 128467258961,977123207545039,43013953,131071,3814697134553,524287,
%U 79792266297087713
%N Smallest prime in the set of primes of the form x^n - y^(n-1), 1<=x, 1<=y.
%C The function x^n -y^(n-1) has some prime values if x and y are covering the first quadrant. The smallest of these primes defines a(n).
%e 3^1 - 1^0 = 2, 2^2 - 2 = 2, 3^3 - 5^2 = 2, so 2,2,2 are the first 3 entries.
%o (PARI) diffpowers(n,m) =
%o {
%o local(a,c=0,c2=0,j,k,y);
%o a=vector(floor(n^2/log(n^2)));
%o for(j=1,n,
%o for(k=1,n,
%o y=j^m-k^(m-1);
%o if(ispseudoprime(y), c++; a[c]=y;);
%o );
%o );
%o a=vecsort(a);
%o for(j=2,length(a),
%o if(a[j]!=a[j-1]&&a[j]!=0, c2++; print1(a[j]","); if(c2>100,break););
%o );
%o }
%K nonn
%O 1,1
%A _Cino Hilliard_, Jun 17 2009
%E Definition reworded - _R. J. Mathar_, Aug 30 2010
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