# A045694 (b-file synthesized from sequence entry) 1 1 2 2 3 6 4 16 5 48 6 138 7 414 8 1226 9 3678 10 10986 11 32958 12 98736 13 296208 14 888210 15 2664630 16 7992664 17 23977992 18 71930298 19 215790894 20 647361696 21 1942085088 22 5826222306 23 17478666918 24 52435902018 25 157307706054 26 471922821954 27 1415768465862