# A149577 (b-file synthesized from sequence entry) 0 1 1 1 2 5 3 15 4 51 5 199 6 755 7 2821 8 11457 9 45421 10 180609 11 740097 12 3026837 13 12362553 14 51258493 15 213094839 16 885144315 17 3704575695 18 15563367115 19 65372995019 20 275716820519 21 1166762781235 22 4940175457887 23 20965390531703 24 89209748891747 25 379961694898047 26 1620676281126587 27 6926567928761055