# A283612 (b-file synthesized from sequence entry) 0 1 1 1 2 4 3 13 4 57 5 252 6 1322 7 7361 8 45057 9 294392 10 2054394 11 15172872 12 118175823 13 966300054 14 8268640847 15 73825951226 16 686049132714 17 6620780612228 18 66224775509130 19 685372810735380 20 7327272883303533