This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A076707 #5 Mar 30 2012 17:30:50 %S A076707 1,2,3,4,5,10,12,16,17,18,30,38,41,46,54,72,74,94,120,128,138,139,168, %T A076707 186,199,240,248,250,260,271,286,288,312,316,354,356,370,408,424,432, %U A076707 496,546,552,582,600,602,618,678,720,768,792,836,840,876,890,894,912 %N A076707 Ordered differences without repetitions between two successive prime powers of prime numbers. %C A076707 Several entries are represented by at least two differences: 4 (which equals 8-4 & 125-121), 168, 312, 600, 768, 792, 912, 1848, 2472, etc. %e A076707 250 = 161051 - 160801 = 11^5 - 401^2. %t A076707 pp = Sort[ Flatten[ Table[ Prime[n]^Prime[i], {n, 1, PrimePi[ Sqrt[10^16]]}, {i, 1, PrimePi[ Floor[ Log[ Prime[n], 10^16]]]}]]]; l = Length[pp]; b = Take[pp, -l + 1] - Take[pp, l - 1]; Take[ Union[a], 57] %Y A076707 Cf. A053810, A075308, A077257, A077258. %K A076707 nonn %O A076707 1,2 %A A076707 _Zak Seidov_, Oct 26 2002 %E A076707 Edited and corrected by _Robert G. Wilson v_, Oct 31 2002