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%I #5 Mar 30 2012 17:34:50
%S 1,4,17,801528,187117320,17036037480
%N Least number which can be represented by the difference between two successive powers of a prime but not a prime (A077273) in just n ways.
%e 1 = 9-8, 4 = 8-4 & 125-121, 17 = 49 - 32 = 81 -64 = 529 - 512, 801528 = 1115760409 - 1114958881 = 4461839209 - 4461037681 = 10038637249 - 10037835721 = 40153346689 - 40152545161 and
%e 187117320 = 9725896737769 - 9725709620449 = 21883150711249 - 21882963593929 = 60786363426721 - 60786176309401 = 243145173030769 - 243144985913449 = 2188305808807561 - 2188305621690241.
%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]];
%Y Cf. A025475.
%K more,nonn
%O 1,2
%A _Robert G. Wilson v_, Oct 31 2002
%E a(6) from _Donovan Johnson_, Jun 19 2008
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