OFFSET
1,1
COMMENTS
Even numbers are permitted since 9 is an integer square. - Charles R Greathouse IV, Oct 12 2015
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..116 from Daniel Lignon)
MATHEMATICA
eulerPseudo9Q[n_]:=(Mod[9^((n-1)/2)+1, n]==0 ||Mod[9^((n-1)/2)-1, n]==0) && Not[PrimeQ[n]];
Select[Range[2, 200000], eulerPseudo9Q]
PROG
(PARI) is(n) = abs(centerlift(Mod(3, n)^(n-1)))==1 && !isprime(n) && n>1 \\ Charles R Greathouse IV, Oct 12 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Daniel Lignon, Oct 12 2015
STATUS
approved