c Petersen graph 3-coloring, SAT
p cnf 30 85
1 2 3 0
-1 -2 0
-1 -3 0
-2 -3 0
4 5 6 0
-4 -5 0
-4 -6 0
-5 -6 0
7 8 9 0
-7 -8 0
-7 -9 0
-8 -9 0
10 11 12 0
-10 -11 0
-10 -12 0
-11 -12 0
13 14 15 0
-13 -14 0
-13 -15 0
-14 -15 0
16 17 18 0
-16 -17 0
-16 -18 0
-17 -18 0
19 20 21 0
-19 -20 0
-19 -21 0
-20 -21 0
22 23 24 0
-22 -23 0
-22 -24 0
-23 -24 0
25 26 27 0
-25 -26 0
-25 -27 0
-26 -27 0
28 29 30 0
-28 -29 0
-28 -30 0
-29 -30 0
-1 -4 0
-2 -5 0
-3 -6 0
-4 -7 0
-5 -8 0
-6 -9 0
-7 -10 0
-8 -11 0
-9 -12 0
-10 -13 0
-11 -14 0
-12 -15 0
-13 -1 0
-14 -2 0
-15 -3 0
-16 -22 0
-17 -23 0
-18 -24 0
-22 -28 0
-23 -29 0
-24 -30 0
-28 -19 0
-29 -20 0
-30 -21 0
-19 -25 0
-20 -26 0
-21 -27 0
-25 -16 0
-26 -17 0
-27 -18 0
-1 -16 0
-2 -17 0
-3 -18 0
-4 -19 0
-5 -20 0
-6 -21 0
-7 -22 0
-8 -23 0
-9 -24 0
-10 -25 0
-11 -26 0
-12 -27 0
-13 -28 0
-14 -29 0
-15 -30 0