A064239 Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,5.

6, 36, 306, 366, 546, 726, 966, 1296, 2556, 3066, 3696, 3876, 4506, 6036, 6216, 7686, 9126, 9276, 9906, 10596, 10656, 10836, 11286, 12516, 13146, 14196, 14406, 14736, 16266, 17106, 18216, 19416, 19476, 20406, 22146, 22806, 23766

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@ 23800, PrimeQ[# + 1] && PrimeQ[2# + 1] && PrimeQ[5# + 1] &&
CarmichaelNbrQ[(# + 1)(2# + 1)(5# + 1)] &] (* Robert G. Wilson v, Aug 23 2012 *)

Extensions

Offset corrected by Amiram Eldar, Oct 16 2019