OFFSET
1,1
COMMENTS
Most Carmichael numbers are congruent to 1 modulo 6. Those that are not are observed to include numbers that are 5 modulo 6 as well as multiples of 3.
No member of this sequence is divisible by any prime of the form 6k+1, hence all prime factors for this sequence are members of A045410.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000 (calculated using data from Claude Goutier; terms 1..426, below 10^16, based on Richard Pinch data, from Giovanni Resta)
Claude Goutier, Compressed text file carm10e22.gz containing all the Carmichael numbers up to 10^22.
Richard G. E. Pinch, Tables relating to Carmichael numbers.
MAPLE
select(t -> t mod numtheory:-lambda(t) = 1, [seq(6*k+3, k=1..10^6)]); # Robert Israel, Jul 12 2015
MATHEMATICA
Cases[Range[555, 10^6, 6], n_/; Mod[n, CarmichaelLambda[n]]==1]
PROG
(PARI) Korselt(n)=my(f=factor(n)); for(i=1, #f[, 1], if(f[i, 2]>1||(n-1)%(f[i, 1]-1), return(0))); 1
is(n)=n%6==3 && Korselt(n) && n>9 \\ Charles R Greathouse IV, Jul 20 2015
KEYWORD
nonn
AUTHOR
Fred Patrick Doty, Jun 10 2015
STATUS
approved