Principal diagonal of the convolution array A213831.

Terms

a(0) =1a(1) =19a(2) =78a(3) =202a(4) =415a(5) =741a(6) =1204a(7) =1828a(8) =2637a(9) =3655a(10) =4906a(11) =6414a(12) =8203a(13) =10297a(14) =12720a(15) =15496a(16) =18649a(17) =22203a(18) =26182a(19) =30610a(20) =35511a(21) =40909a(22) =46828a(23) =53292a(24) =60325a(25) =67951a(26) =76194a(27) =85078a(28) =94627a(29) =104865