# A225316 (b-file synthesized from sequence entry) 0 1 1 2 2 6 3 18 4 42 5 108 6 270 7 594 8 1350 9 3008 10 6678 11 14620 12 31724 13 67712 14 143792 15 305856 16 651126 17 1377918 18 2908308 19 6120672 20 12848472 21 26854938 22 55963260 23 116389896 24 241526012 25 500796416 26 1037764968 27 2147851712 28 4440630150 29 9176799780 30 18946755918 31 39092425578 32 80569691202