OFFSET
1,3
COMMENTS
Let E be the elliptic curve defined by y^2 = x^3 + 8*x^2 + 36*x + 288 and let P be the point (8, -40) on E. Baranczuk-Naskrecki-Verzobio proved that a(n) is the product of all primes > 5 which divide the denominator of the x-coordinate of n*P. - Robin Visser, Oct 22 2023
LINKS
Stefan Baranczuk, Bartosz Naskrecki, and Matteo Verzobio, Divisibility sequences related to abelian varieties isogenous to a power of an elliptic curve, arXiv:2309.09699 [Math.NT], Sep 18 2023.
PROG
(Sage)
def a(n):
E = EllipticCurve([0, 8, 0, 36, 288])
ans = 1
for pp in factor((n*E(8, -40))[0].denominator()):
if pp[0] > 5: ans *= pp[0]
return ans # Robin Visser, Oct 22 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Oct 11 2023
EXTENSIONS
More terms from Robin Visser, Oct 22 2023
STATUS
approved