A065698 Numbers m such that N = (am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,61.

5580, 19488, 22050, 86466, 140268, 173208, 177966, 227010, 233598, 265806, 273126, 355110, 395736, 402690, 432336, 476988, 486138, 550188, 578370, 588618, 754416, 788088, 844086, 1044288, 1092600, 1204596, 1217406, 1386498, 1415778, 1446888, 1463358, 1563276, 1566936, 1599876

Offset: 1

Author

Harvey Dubner (harvey(AT)dubner.com), Nov 14 2001

Keywords

• nonn

Links

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

Crossrefs

Cf. A064238-A064262, A065695-A065703, A087788.

Programs

Mathematica

CarmichaelNbrQ[n_] := ! PrimeQ@n && Mod[n, CarmichaelLambda@ n] == 1; Select[ Range@ 1600000, PrimeQ[# +1] && PrimeQ[2# +1] && PrimeQ[61# +1] &&  CarmichaelNbrQ[(# +1) (2# +1) (61# +1)] &] (* Robert G. Wilson v, Jul 31 2017 *)

Formula

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

Extensions

a(8) onward from Robert G. Wilson v, Jul 31 2017