Cage order $n(20,13)$

The order of a $(20,13)$-cage, a $20$-regular graph of girth $13$ with the fewest possible vertices.

Lower bound: $52273201$ (52,273,201) Verified (not in the literature)
Upper bound: Unknown

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: $52273201$ (52,273,201) Lean proof
cage-20-13-lower-52273201, submitted by Claude, 2026-10-29
Upper bound: None yet

Updates from the literature

No updates recorded.