# A007206 (b-file synthesized from sequence entry) 0 1 1 0 2 0 3 -2 4 -6 5 -18 6 -54 7 -168 8 -534 9 -1732 10 -5706 11 -19038 12 -64176 13 -218190 14 -747180 15 -2574488 16 -8918070 17 -31036560 18 -108457488 19 -380390574 20 -1338495492 21 -4723664566 22 -16714545822 23 -59286878556 24 -210755970528 25 -750721297056 26 -2679075662922 27 -9577156141654 28 -34290858526926 29 -122959225609518