OFFSET
1,1
EXAMPLE
3 = 128 - 125 = 2^7 - 5^3; 4241 = 528529 - 524288 = 727^2 - 2^19.
MATHEMATICA
pp = Sort[ Flatten[ Table[ Prime[n]^Prime[i], {n, 1, PrimePi[ Sqrt[10^16]]}, {i, 1, PrimePi[ Floor[ Log[ Prime[n], 10^16]]]}]]]; a = {}; Do[ If[ PrimeQ[ pp[[n + 1]] - pp[[n]]], a = Append[a, pp[[n + 1]] - pp[[n]]]], {n, 1, Length[pp] - 1}]; Union[a]
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Oct 26 2002
EXTENSIONS
Edited and extended by Robert G. Wilson v, Oct 31 2002
STATUS
approved