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.

A240164 Numbers n such that (k!+n)/k and (k!-n)/k are prime for some k.

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%I A240164 #31 Aug 21 2014 22:41:13
%S A240164 4,25,35,42,65,66,85,95,102,114,121,133,152,170,186,204,222,259,279,
%T A240164 282,296,318,328,333,354,366,376,438,451,462,469,474,536,539,546,583,
%U A240164 584,603,618,623,642,654,678,682,707,721,749,833,856,931,938,963,1001,1048,1062,1079,1099,1141
%N A240164 Numbers n such that (k!+n)/k and (k!-n)/k are prime for some k.
%C A240164 Subsequence of intersection of A240161 and A240163. [Corrected by _Jens Kruse Andersen_, Aug 04 2014]
%C A240164 By using Wilson's theorem, we can show that each term of the sequence is composite. - _Farideh Firoozbakht_, Aug 02 2014
%o A240164 (PARI)
%o A240164 a(n)=for(k=1,n,s=(k!+n)/k;t=(k!-n)/k;if(floor(s)==s&&floor(t)==t,if(ispseudoprime(s)&&ispseudoprime(t),return(k))))
%o A240164 n=1;while(n<10^3,if(a(n),print1(n,", "));n++)
%Y A240164 Cf. A240161, A240163.
%K A240164 nonn
%O A240164 1,1
%A A240164 _Derek Orr_, Aug 01 2014