OFFSET
1,1
LINKS
Eric M. Schmidt, Table of n, a(n) for n = 1..100
E. Lehmer, Artiads characterized, J. Math. Anal. Appl. 15 1966 118-131. See p. 128, Theorem 7.
E. Lehmer, Artiads characterized, J. Math. Anal. Appl. 15 1966 118-131 [annotated and corrected scanned copy]
PROG
(Sage)
def isa(n) :
if not (n % 98 == 1 and is_prime(n)) : return False
R.<t> = PolynomialRing(GF(n))
return 2.powermod((n-1)//7, n) == 1 and all(r[0]^((n-1)//7) == 1 for r in (t^3 + t^2 - 2*t - 1).roots())
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric M. Schmidt, Apr 03 2016
STATUS
approved