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 A107744 #26 Nov 03 2024 02:03:55 %S A107744 7,13,19,5,31,37,43,7,5,61,67,73,79,5,7,97,103,109,5,11,127,7,139,5, %T A107744 151,157,163,13,5,181,11,193,199,5,211,7,223,229,5,241,13,11,7,5,271, %U A107744 277,283,17,5,7,307,313,11,5,331,337,7,349,5,19,367,373,379,5,17,397,13,409 %N A107744 Smallest prime factor of 6*n+1. %C A107744 If 6*n+1 is prime, a(n) = 6*n+1. %H A107744 Amiram Eldar, <a href="/A107744/b107744.txt">Table of n, a(n) for n = 1..10000</a> %F A107744 a(n) = A020639(A016921(n)). - _Amiram Eldar_, Nov 03 2024 %t A107744 A107744[n_]:= FactorInteger[6 n + 1][[1, 1]] %o A107744 (PARI) vector(100, n, vecmin(factor(6*n+1)[, 1])) \\ _Altug Alkan_, Oct 23 2015 %o A107744 (Magma) [Min(PrimeFactors(6*n+1)):n in[1..68]]; // _Jason Kimberley_, Oct 28 2015 %Y A107744 Cf. A016921, A020639. %Y A107744 Cf. A107745 (smallest prime factor of 6*n-1), A107746 (values of k such that A107744(k) > A107745(k)), A107747 (values of k such that A107744(k) < A107745(k)). %K A107744 nonn %O A107744 1,1 %A A107744 _Zak Seidov_, May 23 2005 %E A107744 Comments corrected and (at the suggestion of _Michel Marcus_) moved to Crossrefs by _Jason Kimberley_, Oct 23 2015