Diagonal sums of number array A082043.

Terms

a(0) =1a(1) =2a(2) =6a(3) =20a(4) =59a(5) =150a(6) =336a(7) =680a(8) =1269a(9) =2218a(10) =3674a(11) =5820a(12) =8879a(13) =13118a(14) =18852a(15) =26448a(16) =36329a(17) =48978a(18) =64942a(19) =84836a(20) =109347a(21) =139238a(22) =175352a(23) =218616a(24) =270045a(25) =330746a(26) =401922a(27) =484876a(28) =581015a(29) =691854