Source of the n=73 phase witness
Retrieved on 23 August 2026 from Achim Flammenkamp's
no-three-in-line database.
The notes credit Marijn Heule with the first solution, found on
19 August 2026 in symmetry class rct4.
The exact entry came from the documented lookup endpoint with POST fields
symm=c, size=73, and index=1; the response reported database cut date
19 August 2026. n73-rct4.code is the untouched one-line encoding. It is used
only to choose SAT phases for the complete formula.