A138273 Column 1 of triangle A138271; also, column 0 of matrix power A138271^2.
1, 2, 10, 78, 798, 9874, 141282, 2273730, 40400466, 782174594, 16339339034, 365507560686, 8703242020078, 219514664265570, 5840845740086722, 163388004393303378, 4790811699042196754, 146865803196242855938
Offset: 0