# A153987 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 3 4 5 5 12 6 33 7 97 8 381 9 1490 10 7757 11 42774 12 307960 13 2294754 14 22718581 15 231171797 16 3121763126 17 43651298703 18 807916379400 19 15440457456928 20 391605380566734 21 10243338678890245 22 355535039683009851