a(n) = floor( n*(n-1)*(n-2)/29 ).

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =2a(6) =4a(7) =7a(8) =11a(9) =17a(10) =24a(11) =34a(12) =45a(13) =59a(14) =75a(15) =94a(16) =115a(17) =140a(18) =168a(19) =200a(20) =235a(21) =275a(22) =318a(23) =366a(24) =418a(25) =475a(26) =537a(27) =605a(28) =677a(29) =756