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 A077273 #2 Mar 30 2012 17:30:51
%S A077273 1,2,3,4,5,7,9,10,12,13,15,17,18,30,33,38,40,41,54,63,74,94,96,104,
%T A077273 112,120,128,138,139,151,168,186,192,199,240,248,250,255,260,271,286,
%U A077273 288,298,307,312,316,320,354,356,362,375,393,408,423,424,432,496,504,513
%N A077273 Ordered differences without repetitions between two successive powers of a prime but not a prime (A025475).
%e A077273 33 = 546 - 513 = 2568 - 2535 = 6168 - 6135 = 458703 - 458670 = 885465 - 885432 = 1048608 - 1048575 = 6291480 - 6291447 = 37748688 - 37748655 = 125829345 - 125829312.
%t A077273 pp = Sort[ Flatten[ Table[ Prime[n]^i, {n, 1, PrimePi[ Sqrt[10^16]]}, {i, 1, Log[ Prime[n], 10^16]}]]]; l = Length[pp]; d = Sort[Take[pp, -l + 1] - Take[pp, l - 1]]; Union[ Take[d, 10^5]]
%Y A077273 Cf. A025475.
%K A077273 nonn
%O A077273 1,2
%A A077273 _Robert G. Wilson v_, Oct 31 2002