Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A101186
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A101186 Values of k for which 7m+1, 8m+1 and 11m+1 are prime, with m=1848k+942. +0
3
13, 123, 218, 223, 278, 411, 513, 551, 588, 733, 743, 796, 856, 928, 1168, 1226, 1263, 1401, 1533, 1976, 1981, 2013, 2096, 2138, 2241, 2376, 2556, 2676, 2703, 3626, 3703, 3718, 3971, 4008, 4121, 4138, 4163, 4188, 4211, 4313, 4423, 4653, 4656, 4901, 5018 (list; graph; listen)
OFFSET

1,1

COMMENT

The number (7m+1)(8m+1)(11m+1) is a 3-factor Carmichael number if and only if m is equal to 1848k+942 with k in this sequence. The sequence includes the value k=10^329-4624879 which yields a 1000-digit Carmichael number with three prime factors of 334 digits each. Other Carmichael numbers of the same form would necessarily have 4 prime factors or more; the smallest such example is 3664585=127*(7*29)*199, for m=18.

LINKS

G. P. Michon, Generic Carmichael Numbers.

EXAMPLE

a(1)=13 because k=13 corresponds to m=24966, which yields a product of three primes (7m+1)(8m+1)(11m+1) equal to the Carmichael number 9585921133193329 (among all Carmichael numbers with 16 digits or less, as first listed by Richard G.E. Pinch, this one features the largest "least prime factor").

CROSSREFS

Cf. A002997 (Carmichael numbers). A046025.

Sequence in context: A096053 A033470 A016230 this_sequence A115204 A016277 A134550

Adjacent sequences: A101183 A101184 A101185 this_sequence A101187 A101188 A101189

KEYWORD

nonn

AUTHOR

Gerard P. Michon (g.michon(AT)att.net), Dec 03 2004

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified November 30 22:12 EST 2008. Contains 150989 sequences.


AT&T Labs Research