OFFSET
0,2
COMMENTS
a(n) is the smallest nonnegative k such that A216511(k) = n.
Conjecture: All terms are multiple of a(1) = 8.
a(30) = 5165248.
a(31) = 16386304.
a(32) = 3756544.
a(33) = 11399168.
a(34) = 66322432.
a(35) = 86206208.
a(36) = 7513088.
PROG
(Python)
from itertools import count
from sympy.abc import x, y
from sympy.solvers.diophantine.diophantine import diop_quadratic
def A374159(n): return next(m for m in count(0) if sum(1 for d in diop_quadratic(x**2+7*y**2-m) if d[0]>0 and d[1]>0)==n) # Chai Wah Wu, Jun 30 2024
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Seiichi Manyama, Jun 29 2024
STATUS
approved