# A087222 (b-file synthesized from sequence entry) 0 1 1 1 2 4 3 10 4 26 5 69 6 184 7 488 8 1294 9 3436 10 9116 11 24190 12 64190 13 170334 14 451994 15 1199400 16 3182706 17 8445556 18 22410946 19 59469200 20 157806184 21 418751069 22 1111188772 23 2948626472 24 7824411358 25 20762688580 26 55095420880 27 146200015984