# A075631 (b-file synthesized from sequence entry) 1 1 2 2 3 12 4 156 5 4680 6 42120 7 43931160 8 1489793497920 9 89075729055377937600 10 51745303414377493336016875691726400 11 11120662689162548692119420650118842670724939176955384978536000