# A099488 (b-file synthesized from sequence entry) 0 1 1 2 2 7 3 28 4 105 5 390 6 1455 7 5432 8 20273 9 75658 10 282359 11 1053780 12 3932761 13 14677262 14 54776287 15 204427888 16 762935265 17 2847313170 18 10626317415 19 39657956492 20 148005508553 21 552364077718 22 2061450802319 23 7693439131560 24 28712305723921