# A096168 (b-file synthesized from sequence entry) 0 1 1 3 2 9 3 24 4 66 5 180 6 468 7 1206 8 3150 9 7998 10 20124 11 50520 12 124044 13 303906 14 744870 15 1790226 16 4319322 17 10432044 18 24926934 19 59570514 20 142662384 21 339247320 22 807092274 23 1920506232 24 4543861644