[1,1,4,12,34,100,292,852,2488,7264,21208,61920, 180784,527824,1541056,4499328,13136416,38353600, 111978688,326937408,954539392,2786910976, 8136775552,23756451840,69360276736,202507008256, 591247473664,1726229517312,5039967998464]