Main diagonal of array in A163280.

Terms

a(0) =1a(1) =6a(2) =15a(3) =28a(4) =45a(5) =66a(6) =91a(7) =128a(8) =162a(9) =200a(10) =231a(11) =372a(12) =325a(13) =406a(14) =495a(15) =656a(16) =561a(17) =954a(18) =703a(19) =1180a(20) =987a(21) =1078a(22) =1035a(23) =1896a(24) =1375a(25) =1534a(26) =1701a(27) =2324a(28) =1653a(29) =3090