Column 1 of square array A136730.

Terms

a(0) =1a(1) =2a(2) =5a(3) =23a(4) =175a(5) =1935a(6) =28432a(7) =523290a(8) =11587072a(9) =299942890a(10) =8886126540a(11) =296438370794