# A158661 (b-file synthesized from sequence entry) 0 4 1 4 2 6 3 24 4 60 5 144 6 360 7 852 8 1968 9 4488 10 10068 11 22272 12 48780 13 105948 14 228588 15 490404 16 1046976 17 2225964 18 4715400 19 9956976 20 20965212 21 44031360 22 92262348 23 192920784 24 402629256 25 838827576 26 1744784388 27 3623814864 28 7516104564