OFFSET
1,1
COMMENTS
Also, Carmichael numbers of the form k^2 + k + 1.
Also, Carmichael numbers of the form k^2 - k + 1.
There are no other terms below 10^22.
Carmichael numbers m such that 4m - 3 is square. - Thomas Ordowski, Apr 30 2018
LINKS
CROSSREFS
KEYWORD
nonn,more,hard
AUTHOR
Max Alekseyev, Apr 30 2018
EXTENSIONS
a(6)-a(7) calculated using data from Claude Goutier and added by Amiram Eldar, Apr 20 2024
STATUS
approved