OFFSET
1,2
COMMENTS
The factors may be equal, but no example for n>1 is known.
EXAMPLE
See A394987.
PROG
(Python)
from sympy.utilities.iterables import multiset_permutations
from sympy import divisors
def A394989(n):
a = 1<<n-1
b = a<<1
k = (n<<1)-1
for l in range(k, 0, -1):
for s in multiset_permutations('0'*(k+1-l)+'1'*l):
m = int(''.join(s), 2)
for d in divisors(m):
if d**2>m:
break
if a<=d<b and a*d<=m<b*d:
return d # Chai Wah Wu, Apr 11 2026
CROSSREFS
KEYWORD
nonn,new
AUTHOR
Hugo Pfoertner, Apr 09 2026
EXTENSIONS
a(24)-a(35) from Chai Wah Wu, Apr 10 2026
STATUS
approved