a(n) = Sum of all divisors of all numbers < (n+1)^2.

Terms

a(0) =8a(1) =56a(2) =189a(3) =491a(4) =1007a(5) =1930a(6) =3276a(7) =5314a(8) =8082a(9) =11973a(10) =16783a(11) =23355a(12) =31314a(13) =41380a(14) =53566a(15) =68510a(16) =85771a(17) =106981a(18) =130973a(19) =159470a(20) =192020a(21) =229762a(22) =271873a(23) =320779a(24) =375031a(25) =436311a(26) =504464a(27) =581422a(28) =664364a(29) =759025