A115324 Central terms of the rows of triangle A115323.

1, 1, 2, 4, 9, 22, 55, 141, 371, 997, 2712, 7440, 20542, 57056, 159343, 447045, 1259443, 3561529, 10119910, 28892841, 82727805, 237322575, 681862156, 1961930899, 5653182325, 16312268162, 47133250093, 136366337701