1, 1, 3, 7, 23, 69, 241, 815, 2973, 10765, 40599, 153519, 594441, 2315819, 9159005, 36470431, 146745519, 594261517, 2425275509, 9954790549, 41110526691, 170626390065, 711716332495, 2981638200405, 12543716384153, 52971343747061, 224502013317731, 954637799193723, 4072108059395579