# A033280 (b-file synthesized from sequence entry) 0 1 1 27 2 385 3 4004 4 34398 5 259896 6 1790712 7 11511720 8 70114902 9 409003595 10 2303105805 11 12593413560 12 67173369900 13 350777861280 14 1798432526880 15 9073909567440 16 45140379405030 17 221768094898350 18 1077403874372826 19 5182007298602904 20 24699073588138180 21 116759256962107760