OFFSET
1,1
COMMENTS
Wright (2012) proves that given the 5 known Fermat primes (A019434), these are the only numbers possible.
LINKS
Eric Weisstein's World of Mathematics, Carmichael Function.
Thomas Wright, The impossibility of certain types of Carmichael numbers, INTEGERS 12 (2012), A31.
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
T. D. Noe, Jul 19 2012
STATUS
approved