A263029 Numbers n such that A002322(n) + 1 is not a prime, where A002322 is Carmichael lambda.

25, 32, 50, 55, 75, 81, 96, 100, 110, 115, 119, 121, 128, 150, 153, 160, 162, 165, 176, 187, 200, 203, 209, 215, 220, 221, 224, 230, 235, 238, 242, 245, 253, 256, 261, 275, 287, 288, 289, 295, 297, 299, 300, 306, 319, 323, 324, 330, 335, 343, 345, 355

Offset: 1

Author

Vincenzo Librandi, Oct 12 2015

Keywords

• nonn
• easy

Comments

Complement of A263028.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..25794

Crossrefs

Cf. A002322, A263027, A263028.

Positions of zeros in A296077.

Cf. also A039689.

Programs

Magma

[n: n in [2..400] | not IsPrime(CarmichaelLambda(n)+1)];

Mathematica

Select[Range[1, 400], ! PrimeQ[CarmichaelLambda[#] + 1] &]

PARI

for(n=1, 1e3, if(isprime((1 + lcm(znstar(n)[2]))) == 0, print1(n", "))) \\ Altug Alkan, Oct 12 2015