1, 3, 9, 25, 69, 189, 519, 1431, 3969, 11077, 31107, 87867, 249523, 711987, 2040201, 5868009, 16932645, 49000221, 142153251, 413303355, 1203986079, 3513322887, 10267781301, 30048790725, 88045917831, 258268671963, 758350570077, 2228771296357, 6555782946621, 19298241524061, 56848508815063