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A064247 Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,21. 1
30, 198, 366, 576, 618, 828, 1626, 2466, 2550, 3390, 4860, 4986, 5658, 6036, 6120, 6708, 6960, 7506, 12966, 13218, 13680, 15318, 16746, 18048, 18678, 19476, 20946, 21030, 21786, 22668, 23130, 23676, 23760, 25608, 26406, 26700 (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).

REFERENCES

Harvey Dubner (harvey(AT)dubner.com), personal communication, Jun 27 2001.

LINKS

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

MATHEMATICA

CarmichaelNbrQ[n_] := ! PrimeQ@ n && Mod[n, CarmichaelLambda@ n] == 1; Select[ Range@ 30000, PrimeQ[# + 1] && PrimeQ[2# + 1] && PrimeQ[21# + 1] && CarmichaelNbrQ[(# + 1)(2# + 1)(21# + 1)] &] (* Robert G. Wilson v, Aug 23 2012 *)

CROSSREFS

Cf. A087788.

Sequence in context: A309924 A120339 A319334 * A125340 A126498 A029545

Adjacent sequences:  A064244 A064245 A064246 * A064248 A064249 A064250

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 January 23 03:15 EST 2022. Contains 350504 sequences. (Running on oeis4.)