1,1

These numbers:

- are pseudoprimes to bases 2, 3 and 5;

- do not occur in A097130 (Carmichael numbers that are not == 1 mod 24).

The number (6*k + 1)*(24*k + 1)*(30*k + 1) is in the sequence if:

- k is congruent to 5 mod 10;

- its three factors are all prime.

Amiram Eldar, Table of n, a(n) for n = 1..1000

Eric Weisstein's World of Mathematics, Carmichael Number

Index entries for sequences related to Carmichael numbers

Index entries for sequences related to pseudoprimes

(MAGMA) [a : k in [1..1785 by 2] | IsOne(a mod CarmichaelLambda(a)) where a is (6*k+1)*(24*k+1)*(30*k+1)]

Subsequence of A002997 and of A083737. Supersequence of A230746.

Sequence in context: A175691 A133220 A023086 * A251016 A251027 A204149

Adjacent sequences: A230719 A230720 A230721 * A230723 A230724 A230725

nonn

Arkadiusz Wesolowski, Oct 28 2013

approved