Principal diagonal of the convolution array A213505.

Terms

a(0) =1a(1) =25a(2) =170a(3) =674a(4) =1979a(5) =4795a(6) =10164a(7) =19524a(8) =34773a(9) =58333a(10) =93214a(11) =143078a(12) =212303a(13) =306047a(14) =430312a(15) =592008a(16) =799017a(17) =1060257a(18) =1385746a(19) =1786666a(20) =2275427a(21) =2865731a(22) =3572636a(23) =4412620a(24) =5403645a(25) =6565221a(26) =7918470a(27) =9486190a(28) =11292919a(29) =13364999