# A094434 (b-file synthesized from sequence entry) 1 0 2 2 3 12 4 60 5 288 6 1368 7 6480 8 30672 9 145152 10 686880 11 3250368 12 15380928 13 72783360 14 344414592 15 1629787392 16 7712236800 17 36494696448 18 172694757888 19 817200368640 20 3867033664512 21 18298999775232 22 86591796664320 23 409756781334528