a(n) = floor(n/2) * floor(n/3).

Terms

a(0) =0a(1) =0a(2) =1a(3) =2a(4) =2a(5) =6a(6) =6a(7) =8a(8) =12a(9) =15a(10) =15a(11) =24a(12) =24a(13) =28a(14) =35a(15) =40a(16) =40a(17) =54a(18) =54a(19) =60a(20) =70a(21) =77a(22) =77a(23) =96a(24) =96a(25) =104a(26) =117a(27) =126a(28) =126a(29) =150