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.

A125163 Numbers m such that no prime exists of the form k! + m; or A125162(m) = 0.

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%I A125163 #22 Dec 16 2024 19:15:51
%S A125163 8,14,20,24,26,32,33,34,38,44,48,50,54,56,62,63,64,68,74,75,76,80,84,
%T A125163 86,90,92,93,94,98,104,110,114,116,117,118,120,122,123,124,128,132,
%U A125163 134,140,141,142,144,146,152,153,154,158,159,160,164,168,170,174,176,182,183,184,186,188,194,200,201,202,204,206,207,208,212
%N A125163 Numbers m such that no prime exists of the form k! + m; or A125162(m) = 0.
%C A125163 Terms are the indices of zeros in A125162, i.e. A125162[a(n)] = 0.
%e A125163 A125162 begins {1,1,1,1,3,1,4,0,1,1,5,1,3,0,1,1,6,1,7,0,1,1,6,0,1,0,1,1,6,1,9,0,0,0,3,1,11,0,1,1,9,1,5,0,1,1,10,0,2,0,1,1,9,0,2,0,1,1,10,1,9,0,0,0,3,1,9,0,1,1,8,1,9,0,0,0,5,1,9,0,1,1,11,0,1,0,1,1,8,0,3,0,0,0,2,1,10,0,1,1,...}.
%e A125163 Thus a(1) = 8, a(2) = 14, a(3) = 20, a(4) = 24, a(5) = 26, a(6)-a(8) = {32,33,34}.
%t A125163 k={};Do[If[Length[Select[Range[m],PrimeQ[#!+m]&]]==0,AppendTo[k,m]],{m,212}];k (* _James C. McMahon_, Dec 16 2024 *)
%o A125163 (PARI) b(n)=c=0;for(k=1,n,if(ispseudoprime(k!+n),c++));c
%o A125163 n=1;while(n<500,if(!b(n),print1(n,", "));n++) \\ _Derek Orr_, Oct 15 2014
%Y A125163 Cf. A125162 = number of primes of the form k! + n. Cf. A125164 = numbers n such that no prime exists of the form (k! + 3n - 1), (k! + 3n), (k! + 3n + 1).
%K A125163 nonn
%O A125163 1,1
%A A125163 _Alexander Adamchuk_, Nov 21 2006
%E A125163 More terms from _Derek Orr_, Oct 15 2014
%E A125163 Edited by _Michel Marcus_, Jul 29 2018