# A151495 (b-file synthesized from sequence entry) 0 1 1 1 2 6 3 22 4 112 5 556 6 2992 7 16416 8 93040 9 537004 10 3156300 11 18805948 12 113415860 13 690920348 14 4246311084 15 26297470908 16 163962253192 17 1028405157316 18 6484807032820 19 41086983729464 20 261446728122772 21 1670163037965324 22 10707288651740680 23 68867225024134936 24 444264596237129308 25 2873850125874850068