OFFSET
1,1
COMMENTS
This elliptic curve corresponds to a weight 2 newform which is an eta-quotient, namely, (eta(4t)*eta(20t))^6 / (eta(2t)*eta(8t)*eta(10t)*eta(40t))^2, see Theorem 2 in Martin & Ono.
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..10000
Yves Martin and Ken Ono, Eta-Quotients and Elliptic Curves, Proc. Amer. Math. Soc. 125, No 11 (1997), 3169-3176.
FORMULA
a(n) gives the number of solutions of the congruence y^2 == x^3 - x^2 + 4*x - 4 (mod prime(n)), n >= 1.
EXAMPLE
The first nonnegative complete residue system {0, 1, ..., prime(n)-1} is used.
The solutions (x, y) of y^2 == x^3 - x^2 + 4*x - 4 (mod prime(n)) begin:
n, prime(n), a(n)\ solutions (x, y)
1, 2, 2: (0, 0), (1, 0)
2, 3, 1: (1, 0)
3, 5, 6: (0, 1), (0, 4), (1, 0),
(3, 1), (3, 4), (4, 0)
4, 7, 9: (1, 0), (2, 1), (2, 6),
(4, 2), (4, 5), (5, 2),
(5, 5), (6, 2), (6, 5)
PROG
(Ruby)
require 'prime'
def A276664(n)
ary = []
Prime.take(n).each{|p|
a = Array.new(p, 0)
(0..p - 1).each{|i| a[(i * i) % p] += 1}
ary << (0..p - 1).inject(0){|s, i| s + a[(i * i * i - i * i + 4 * i - 4) % p]}
}
ary
end
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Sep 12 2016
STATUS
approved