# A151288 (b-file synthesized from sequence entry) 0 1 1 2 2 6 3 22 4 84 5 336 6 1392 7 5912 8 25580 9 112324 10 499312 11 2242188 12 10154664 13 46324964 14 212664488 15 981653620 16 4553218968 17 21209894268 18 99178882232 19 465362985740 20 2190341893320 21 10338437549876 22 48922967035664 23 232055129413436 24 1103080339515552 25 5253968486241476 26 25070738463476960 27 119836239979700524