exact-arithmetic systems checked: 4000 (square: 2212, other p: 1788), max N = 40, 23 s
by number of sides p of K: {3: 470, 4: 2212, 5: 479, 6: 482, 7: 357}
bound sum k_j = 6N'+p-6 attained in 507 systems (by p: {3: 75, 4: 211, 5: 80, 6: 73, 7: 68})
systems with N' < N: 3214;  systems with a vertex of degree >= 4: 480
violations / failed checks: 0
RESULT PASS
