A064242 Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,11.

378, 576, 1236, 3018, 7506, 9090, 18396, 26250, 27966, 28098, 28428, 31068, 32190, 32586, 34500, 35490, 40506, 42156, 46446, 47700, 48888, 50670, 53376, 55290, 55818, 58788, 65256, 65718, 68226, 73308, 74760, 75618, 77730, 86178

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@ 88000, PrimeQ[# + 1] && PrimeQ[2# + 1] && PrimeQ[11# + 1] && CarmichaelNbrQ[(# + 1)(2# + 1)(11# + 1)] &] (* Robert G. Wilson v, Aug 23 2012 *)

Extensions

Offset corrected by Amiram Eldar, Oct 16 2019