A027101 a(n) = diagonal sum of right justified array T given by A027082.
1, 1, 3, 9, 18, 49, 127, 331, 883, 2376, 6439, 17591, 48347, 133589, 370883, 1033997, 2893498, 8124303, 22880569, 64616728, 182943204, 519146325, 1476337528, 4206621803, 12008000771, 34335363519, 98332343337, 282026580873
Offset: 0