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A036060 Number of 3-component Carmichael numbers C = (6M+1)(12M+1)(18M+1) < 10^n. 0
0, 1, 1, 2, 2, 3, 7, 10, 16, 27, 45, 77, 133, 234, 415, 746, 1354, 2480, 4580, 8519, 15956, 30069, 56988, 108570, 207836, 399638, 771621, 1495580, 2909178, 5677865, 11116339, 21828157, 42670184, 84144873, 166369603, 318733896 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,4

COMMENTS

Note that this is different from the count of 3-Carmichael numbers, A132195. The numbers counted here are neither those listed in A087788 (3 arbitrary prime factors) nor those listed in A033502 (where 6m+1, 12m+1 and 18m+1 are all prime). - M. F. Hasler, Apr 14 2015

REFERENCES

Posting by Harvey Dubner (harvey(AT)dubner.com) to Number Theory List (NMBRTHRY(AT)LISTSERV.NODAK.EDU), Nov 23 1998.

LINKS

Table of n, a(n) for n=3..38.

H. Dubner, 3-Component Carmichael Numbers-correction

Index entries for sequences related to Carmichael numbers.

CROSSREFS

Cf. A002997, A132195, A087788, A055553, A033502.

Sequence in context: A043550 A237988 A208494 * A227300 A065383 A087384

Adjacent sequences:  A036057 A036058 A036059 * A036061 A036062 A036063

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified May 27 22:57 EDT 2017. Contains 287210 sequences.