# A091363 (b-file synthesized from sequence entry) 0 0 1 1 2 16 3 162 4 1536 5 15000 6 155520 7 1728720 8 20643840 9 264539520 10 3628800000 11 53129260800 12 827714764800 13 13680764697600 14 239217231052800 15 4413400992000000 16 85699747381248000 17 1747492334235648000 18 37338643451805696000 19 834363743704178688000