%I #2 Mar 30 2012 17:30:51
%S 4,7,17,408,792,912,1608,1848,2472,2912,3192,3288,3432,3528,4008,4080,
%T 4920,5160,5208,5928,6072,6792,6888,7080,7512,7728,7800,8520,8832,
%U 10632,10848,11400,11880,11928,12792,13200,13440,13560,14280,14640
%N Differences between two successive powers of a prime but not a prime (A025475) in more than one way.
%e 4 = 8 - 4 = 125 -121, 7 = 16 - 9 = 32768 - 32761, 17 = 49 - 32 = 81 -64 = 529 - 512, etc.
%t pp = Sort[ Flatten[ Table[ Prime[n]^i, {n, 1, PrimePi[ Sqrt[10^16]]}, {i, 1, Log[ Prime[n], 10^16]]]}]]]; l = Length[pp]; b = Sort[ Take[pp, -l + 1] - Take[pp, l - 1]]; Union[ b[[ Select[ Range[375], b[[ # ]] == b[[ # + 1]] &]]]]
%Y Cf. A025475.
%K nonn
%O 1,1
%A _Robert G. Wilson v_, Oct 31 2002