A064261 Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,49.

660, 2718, 12420, 57990, 82980, 89448, 127080, 142368, 174120, 184998, 202638, 216750, 229980, 233508, 234978, 280548, 297600, 329940, 331998, 341700, 384918, 406380, 412848, 421080, 433428, 455478, 503988, 505458, 533388, 578370, 608358, 675978, 768588, 779760

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

carmQ[n_] := CompositeQ[n] && Divisible[n - 1, CarmichaelLambda[n]]; Select[Range[10^5], AllTrue[(v = {1, 2, 49}*# + 1), PrimeQ] && carmQ[Times @@ v] &] (* Amiram Eldar, Oct 17 2019 *)

Extensions

Offset corrected and more terms added by Amiram Eldar, Oct 17 2019