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 A107747 #27 Nov 03 2024 02:04:05
%S A107747 4,8,9,14,15,19,22,24,28,29,34,39,42,43,44,49,50,53,54,57,59,60,64,65,
%T A107747 67,69,74,75,78,79,80,82,84,85,89,92,93,94,98,99,104,108,109,113,114,
%U A107747 117,119,120,124,127,129,130,133,134,139,140,144,148,149,150,152,154
%N A107747 Numbers k such that the least prime factor of 6*k+1 < the least prime factor of 6*k-1, A107744(k) < A107745(k).
%H A107747 Amiram Eldar, <a href="/A107747/b107747.txt">Table of n, a(n) for n = 1..10000</a>
%t A107747 lpfQ[n_]:=Module[{c=6n},FactorInteger[c+1][[1,1]] < FactorInteger [c-1][[1,1]]]; Select[Range[200],lpfQ] (* _Harvey P. Dale_, Apr 18 2011 *)
%o A107747 (PARI) isok(n) = vecmin(factor(6*n+1)[, 1]) < vecmin(factor(6*n-1)[, 1]);
%o A107747 for(n=1, 200,if(isok(n)==1, print1(n", "))) \\ _Altug Alkan_, Oct 23 2015
%Y A107747 Cf. A107744 (smallest prime factor of 6*n+1), A107745 (smallest prime factor of 6*n-1), A107746 (values of k such that A107744(k) > A107745(k)).
%K A107747 nonn
%O A107747 1,1
%A A107747 _Zak Seidov_, May 23 2005
%E A107747 Comments corrected and (at the suggestion of _Michel Marcus_) moved to Crossrefs by _Jason Kimberley_, Oct 23 2015