Number of distinct values of the sum of 3 products of three 0..n integers.

Terms

a(0) =4a(1) =20a(2) =63a(3) =141a(4) =284a(5) =478a(6) =780a(7) =1156a(8) =1667a(9) =2298a(10) =3111a(11) =4012a(12) =5213a(13) =6520a(14) =8063a(15) =9839a(16) =11943a(17) =14184a(18) =16882a(19) =19667a(20) =22953a(21) =26467a(22) =30431a(23) =34509a(24) =39359a(25) =44396a(26) =49878a(27) =55801a(28) =62298a(29) =68881