A027301 a(n) = self-convolution of row n of Catalan triangle (A008315).
1, 2, 4, 13, 26, 100, 196, 820, 1581, 6954, 13244, 60214, 113620, 528840, 990756, 4692780, 8741876, 41970280, 77824912, 377687453, 697689538, 3415756084, 6289798684, 31018849628, 56964451670, 282658474700, 517885177320
Offset: 0