# A003203 (b-file synthesized from sequence entry) 0 1 1 4 2 12 3 24 4 52 5 108 6 224 7 412 8 844 9 1528 10 3152 11 5036 12 11984 13 15040 14 46512 15 34788 16 197612 17 4036 18 929368 19 -702592 20 4847552 21 -7033956 22 27903296 23 -54403996 24 170579740