Principal diagonal of the convolution array A213558.

Terms

a(0) =1a(1) =91a(2) =1366a(3) =9542a(4) =43535a(5) =151313a(6) =435324a(7) =1089804a(8) =2452269a(9) =5071495a(10) =9794290a(11) =17873362a(12) =31098587a(13) =51953981a(14) =83802680a(15) =131102232a(16) =199652505a(17) =296878515a(18) =432150478a(19) =617143390a(20) =866238439a(21) =1196968553a(22) =1630510388a(23) =2192225060