# A309578 (b-file synthesized from sequence entry) 1 1 2 3 3 8 4 48 5 144 6 329 7 2584 8 15456 9 104005 10 832040 11 1866294 12 34111385 13 267914296 14 1602508992 15 10783446409 16 193501094490 17 1548008755920 18 3472236254411 19 166151337293088 20 498454011879264 21 1118049290473933 22 53500214605455696 23 360008399296352015 24 2460986135945634432