# A108012 (b-file synthesized from sequence entry) 0 0 1 4 2 18 3 76 4 320 5 1360 6 5832 7 25200 8 109568 9 478784 10 2100512 11 9244352 12 40784896 13 180284672 14 798121088 15 3537391360 16 15692333056 17 69661541376 18 309407486464 19 1374824795136 20 6110847909888 21 27168232722432 22 120809925167104