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%I #16 Sep 08 2022 08:46:14
%S 25,32,50,55,75,81,96,100,110,115,119,121,128,150,153,160,162,165,176,
%T 187,200,203,209,215,220,221,224,230,235,238,242,245,253,256,261,275,
%U 287,288,289,295,297,299,300,306,319,323,324,330,335,343,345,355
%N Numbers n such that A002322(n) + 1 is not a prime, where A002322 is Carmichael lambda.
%C Complement of A263028.
%H Antti Karttunen, <a href="/A263029/b263029.txt">Table of n, a(n) for n = 1..25794</a>
%t Select[Range[1, 400], ! PrimeQ[CarmichaelLambda[#] + 1] &]
%o (Magma) [n: n in [2..400] | not IsPrime(CarmichaelLambda(n)+1)];
%o (PARI) for(n=1, 1e3, if(isprime((1 + lcm(znstar(n)[2]))) == 0, print1(n", "))) \\ _Altug Alkan_, Oct 12 2015
%Y Cf. A002322, A263027, A263028.
%Y Positions of zeros in A296077.
%Y Cf. also A039689.
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Oct 12 2015