OFFSET
1,1
COMMENTS
The density of primes in this sequence is 11/21.
If p divides A006720(n) for some n, then the smallest such n is <= (1/2)*((sqrt(p)+1)^2+3).
LINKS
Jeremy Rouse, Table of n, a(n) for n = 1..10000
R. Jones and J. Rouse, Galois Theory of Iterated Endomorphisms, Proceedings of the London Mathematical Society, 100, no. 3 (2010), 763-794.
EXAMPLE
11 is in the sequence because 11 divides A006720(10) = 1529.
PROG
(Magma) [ n : n in [2..500] | IsPrime(n) and (n ne 37) and (Order(EllipticCurve([GF(n)!0, 0, 1, -1, 0])![0, 0, 1]) mod 2 eq 1) ];
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jeremy Rouse, Sep 18 2013
STATUS
approved