cp's OEIS Frontend

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.

A077275 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.

This page as a plain text file.
%I A077275 #5 Mar 30 2012 17:34:50
%S A077275 1,4,17,801528,187117320,17036037480
%N A077275 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 A077275 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 A077275 187117320 = 9725896737769 - 9725709620449 = 21883150711249 - 21882963593929 = 60786363426721 - 60786176309401 = 243145173030769 - 243144985913449 = 2188305808807561 - 2188305621690241.
%t A077275 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 A077275 Cf. A025475.
%K A077275 more,nonn
%O A077275 1,2
%A A077275 _Robert G. Wilson v_, Oct 31 2002
%E A077275 a(6) from _Donovan Johnson_, Jun 19 2008