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 A101187 #22 Mar 10 2024 04:01:53 %S A101187 1,5,6,11,15,22,33,35,45,51,55,56,61,85,96,100,103,105,115,121,195, %T A101187 206,216,225,242,255,276,370,380,426,455,470,506,510,511,550,561,588, %U A101187 609,628,661,700,710,741,800,805,825,871,920,930,975,1025,1060,1115,1140 %N A101187 Values of m for which (6m+1)(12m+1)(18m+1) is a Carmichael number. %C A101187 A046025 is a subsequence giving the values of m for which the three factors are prime, which is a sufficient condition for the product (6m+1)(12m+1)(18m+1) to be a Carmichael number. %H A101187 Amiram Eldar, <a href="/A101187/b101187.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from Bruno Berselli) %H A101187 Harvey Dubner, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL5/Dubner/dubner6.html">Carmichael Numbers of the form (6m+1)(12m+1)(18m+1)</a>, Journal of Integer Sequences, Vol. 5 (2002) Article 02.2.1. %H A101187 Gérard P. Michon, <a href="http://www.numericana.com/answer/modular.htm#chernik">Generic Carmichael Numbers</a>. %t A101187 CarmichaelNbrQ[n_] := ! PrimeQ@ n && Mod[n, CarmichaelLambda@ n] == 1; Select[ Range@ 1200, CarmichaelNbrQ[(6# + 1)(12# + 1)(18# + 1)] &] (* _Robert G. Wilson v_, Aug 23 2012 *) %o A101187 (Magma) [n: n in [1..1200] | IsOne(t mod CarmichaelLambda(t)) where t is (6*n+1)*(12*n+1)*(18*n+1)]; // _Bruno Berselli_, Jan 22 2013 %Y A101187 Cf. A002997 (Carmichael numbers), A046025 (subsequence), A101186. %Y A101187 See also A065703. %K A101187 nonn %O A101187 1,2 %A A101187 _Gerard P. Michon_, Dec 03 2004