# A012536 (b-file synthesized from sequence entry) 0 0 1 2 2 8 3 320 4 15808 5 1429888 6 189299200 7 34859305728 8 8524943044608 9 2667935751684096 10 1040196824976736256 11 494214397360327786496 12 281064144909266002903040 13 188495115535527543004266496