A064245 Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,17.

228, 3186, 5226, 5430, 8286, 13998, 15936, 16650, 19608, 24708, 27258, 31848, 34500, 40926, 41130, 43986, 44496, 50310, 53880, 55410, 55818, 70098, 71118, 73770, 86010, 87540, 108246, 110898, 120996, 124566, 129360, 147516, 166080

Offset: 1

Author

N. J. A. Sloane, Sep 23 2001

Keywords

• nonn

Comments

am+1, bm+1, cm+1 are primes and am | (N-1), bm | (N-1), cm |(N-1).

References

• Harvey Dubner (harvey(AT)dubner.com), personal communication, Jun 27 2001.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A087788.

Programs

Mathematica

CarmichaelNbrQ[n_] := ! PrimeQ@ n && Mod[n, CarmichaelLambda@ n] == 1; Select[ Range@ 170000, PrimeQ[# + 1] && PrimeQ[2# + 1] && PrimeQ[17# + 1] && CarmichaelNbrQ[(# + 1)(2# + 1)(17# + 1)] &] (* Robert G. Wilson v, Aug 23 2012 *)

Extensions

Offset corrected by Amiram Eldar, Oct 16 2019