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 A263028 #19 Sep 08 2022 08:46:14 %S A263028 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,26,27, %T A263028 28,29,30,31,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,51,52, %U A263028 53,54,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,76,77,78,79,80,82,83 %N A263028 Numbers n such that A002322(n) + 1 is a prime, where A002322 is Carmichael lambda. %C A263028 Complement of A263029. %H A263028 Antti Karttunen, <a href="/A263028/b263028.txt">Table of n, a(n) for n = 1..39743</a> %t A263028 Select[Range[1, 100], PrimeQ[CarmichaelLambda[#] + 1] &] %o A263028 (Magma) [1] cat [n: n in [2..100] | IsPrime(CarmichaelLambda(n)+1)]; %o A263028 (PARI) for(n=1, 1e3, if(isprime((1 + lcm(znstar(n)[2]))), print1(n", "))) \\ _Altug Alkan_, Oct 12 2015 %Y A263028 Cf. A002322, A263027, A263029, A296077 (characteristic function). %Y A263028 Cf. also A039698. %K A263028 nonn,easy %O A263028 1,2 %A A263028 _Vincenzo Librandi_, Oct 12 2015 %E A263028 More terms from _Antti Karttunen_, Dec 05 2017