%I #26 Aug 18 2017 18:18:28
%S 0,1,1,2,2,3,7,10,16,25,50,86,150,256,436,783,1435,2631,4765,8766,
%T 16320,30601,57719,109504,208822,400643,771735,1494772,2903761,
%U 5658670,11059937,21696205,42670184,84144873,66369603,329733896,655014986,1303918824,2601139051
%N Number of 3-component Carmichael numbers C = (6M + 1)(12M + 1)(18M + 1) < 10^n.
%C 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
%D Posting by Harvey Dubner (harvey(AT)dubner.com) to Number Theory List (NMBRTHRY(AT)LISTSERV.NODAK.EDU), Nov 23 1998.
%H Amiram Eldar, <a href="/A036060/b036060.txt">Table of n, a(n) for n = 3..42</a>
%H H. Dubner, <a href="http://www.albany.edu/~mark/classes/326/dubner2.html">3-Component Carmichael Numbers-correction</a>, Post to Number Theory List, Nov 23 1998.
%H Harvey Dubner, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL5/Dubner/dubner6.html">Carmichael Numbers of the form (6m+1)(12m+1)(18m+1)</a>, Journal of Integer Sequences, Vol. 5 (2002), Article 02.2.1.
%H <a href="/index/Ca#Carmichael">Index entries for sequences related to Carmichael numbers.</a>
%Y Cf. A002997, A033502, A055553, A087788, A132195.
%K nonn
%O 3,4
%A _N. J. A. Sloane_
%E Terms updated (from Dubner's paper) by _Amiram Eldar_, Aug 11 2017