|
|
A293203
|
|
Numbers k such that A090086(k), the smallest pseudoprime to base k (not necessarily exceeding k), is a Carmichael number.
|
|
3
|
|
|
700, 1040, 1150, 1848, 2590, 2660, 6710, 6862, 7000, 7716, 7852, 8060, 8528, 9275, 9875, 10103, 10640, 11830, 12010, 12688, 13340, 16520, 17350, 17570, 17960, 18130, 18340, 19203, 19272, 19420, 19820, 19978, 20410, 20442, 20480, 20612, 20720, 23016, 23463
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
The corresponding Carmichael numbers are 561, 561, 561, 1105, 561, 561, 1729, 561, 561, 1105, 561, 561, 561, 561, 561, 561, 561, 561, 561, ...
Andrzej Schinzel proved that this sequence is infinite. Conjecture: if A090086(n) is a Carmichael number k, then k < n. - Thomas Ordowski, Aug 08 2018
|
|
LINKS
|
|
|
EXAMPLE
|
700 is the sequence since A090086(700) = 561 is a Carmichael number.
|
|
MATHEMATICA
|
carmichaelQ[n_] := Divisible[n - 1, CarmichaelLambda[n]] && ! PrimeQ[n];
f[n_] := Block[{k = 1}, While[GCD[n, k] > 1 || PrimeQ[k] || PowerMod[n, k - 1, k] != 1, j = k++]; k]; Select[Range[10000], carmichaelQ[f[#]] &] (* after Robert G.Wilson v at A090086 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|