Leading diagonal of A100781.

Terms

a(0) =1a(1) =4a(2) =15a(3) =20a(4) =55a(5) =42a(6) =105a(7) =88a(8) =207a(9) =140a(10) =297a(11) =228a(12) =403a(13) =280a(14) =615a(15) =416a(16) =697a(17) =522a(18) =893a(19) =680a(20) =1281a(21) =726a(22) =1357a(23) =1056a(24) =1725a(25) =1040a(26) =2133a(27) =1372a(28) =2117a(29) =1590