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 A064238 Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,3. 14
 6, 36, 210, 270, 306, 330, 336, 600, 726, 1170, 1236, 1296, 1530, 1656, 2220, 2280, 2556, 3036, 3060, 3066, 4260, 4446, 4800, 4950, 5226, 5580, 5850, 6150, 6360, 6690, 6840, 6966, 7620, 7680, 7686, 7866, 8016, 8166, 8190, 8286, 8520 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS am+1, bm+1, cm+1 are primes and am | (N-1), bm | (N-1), cm |(N-1). All m's are multiples of 6 and m, 2m and 3m divide m(2m+1)(3m+1)-1 automatically. REFERENCES Harvey Dubner (harvey(AT)dubner.com), personal communication, Jun 27 2001. LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 FORMULA a(n) = 6 * A046025(n+1). MATHEMATICA CarmichaelNbrQ[n_] := ! PrimeQ@ n && Mod[n, CarmichaelLambda[n]] == 1; Select[ Range@ 9000, PrimeQ[# + 1] && PrimeQ[2# + 1] && PrimeQ[3# + 1] && CarmichaelNbrQ[(# + 1)(2 # + 1)(3 # + 1)] &] (* Robert G. Wilson v, Aug 23 2012 *) CROSSREFS Cf. A046025, A087788. Sequence in context: A225685 A006812 A111989 * A014336 A268941 A269637 Adjacent sequences:  A064235 A064236 A064237 * A064239 A064240 A064241 KEYWORD nonn AUTHOR N. J. A. Sloane, Sep 23 2001 EXTENSIONS Offset corrected by Amiram Eldar, Oct 16 2019 STATUS approved

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Last modified September 24 12:36 EDT 2021. Contains 347642 sequences. (Running on oeis4.)