Principal diagonal of the convolution array A213566.

Terms

a(0) =1a(1) =13a(2) =59a(3) =183a(4) =476a(5) =1108a(6) =2409a(7) =4993a(8) =10007a(9) =19559a(10) =37504a(11) =70832a(12) =132145a(13) =244029a(14) =446763a(15) =811847a(16) =1465676a(17) =2630836a(18) =4697945a(19) =8350305a(20) =14779671a(21) =26058903a(22) =45784224a(23) =80179968a(24) =139995361a(25) =243755533a(26) =423324539a(27) =733409943