# A063683 (b-file synthesized from sequence entry) 1 1 2 3 3 6 4 21 5 50 6 108 7 364 8 987 9 1938 10 6150 11 17622 12 34776 13 121160 14 306852 15 549000 16 2178309 17 5701290 18 11197764 19 39083988 20 93031050 21 191708244 22 697884066 23 1836283246 24 3605645232 25 11442062750 26 32888033880 27 64700678454