Principal diagonal of the convolution array A213838.

Terms

a(0) =1a(1) =20a(2) =89a(3) =240a(4) =505a(5) =916a(6) =1505a(7) =2304a(8) =3345a(9) =4660a(10) =6281a(11) =8240a(12) =10569a(13) =13300a(14) =16465a(15) =20096a(16) =24225a(17) =28884a(18) =34105a(19) =39920a(20) =46361a(21) =53460a(22) =61249a(23) =69760a(24) =79025a(25) =89076a(26) =99945a(27) =111664a(28) =124265a(29) =137780