Packing $14$ unit circles in an equilateral triangle
OwOUwUOwU, via Wikimedia Commons. CC BY-SA 4.0.
The side length of the smallest equilateral triangle into which $14$ unit circles can be packed.
Lower bound:
Unknown
Upper bound:
$8+2\sqrt{3}$
(≈11.4641)
Updates
-
1961
Upper bound: $8+2\sqrt{3}$
(≈11.4641)
Erdős and Oler in 1961
[via Circles in Triangles, Erich Friedman]