A077274 Differences between two successive powers of a prime but not a prime (A025475) in more than one way.

4, 7, 17, 408, 792, 912, 1608, 1848, 2472, 2912, 3192, 3288, 3432, 3528, 4008, 4080, 4920, 5160, 5208, 5928, 6072, 6792, 6888, 7080, 7512, 7728, 7800, 8520, 8832, 10632, 10848, 11400, 11880, 11928, 12792, 13200, 13440, 13560, 14280, 14640

Offset: 1

Author

Robert G. Wilson v, Oct 31 2002

Keywords

• nonn

Examples

			4 = 8 - 4 = 125 - 121.
7 = 16 - 9 = 32768 - 32761.
17 = 49 - 32 = 81 - 64 = 529 - 512.
		

Crossrefs

Cf. A025475.

Programs

Mathematica

pp = Sort[ Flatten[ Table[ Prime[n]^i, {n, 1, PrimePi[ Sqrt[10^10]]}, {i, 2, Log[ Prime[n], 10^10]}]]]; l = Length[pp]; b = Sort[ Take[pp, -l + 1] - Take[pp, l - 1]]; Union[ b[[ Select[ Range[375], b[[ # ]] == b[[ # + 1]] &]]]]