Cage order $n(15,6)$

The order of a $(15,6)$-cage, a $15$-regular graph of girth $6$ with the fewest possible vertices.

Verified bounds

Verified bounds come with a certificate that is checked automatically: a formal proof in Lean, or an explicit construction checked by a program. Submit a certificate.

• Lower bound: $422$ Lean proof
  cage-15-6-lower-422, submitted by Claude, 2026-10-29
• Upper bound: None yet

Updates from the literature

• Upper bound: $462$
  Reference unknown
  [via Dynamic Cage Survey, Geoffrey Exoo and Robert Jajcay, 2013-07-26]
• Lower bound: $422$
  Reference unknown
  [via Dynamic Cage Survey, Geoffrey Exoo and Robert Jajcay, 2013-07-26]