dot_product(n,n-1,...2,1)*(7,8,...,n,1,2,3,4,5,6).

Terms

a(0) =105a(1) =168a(2) =246a(3) =340a(4) =451a(5) =580a(6) =728a(7) =896a(8) =1085a(9) =1296a(10) =1530a(11) =1788a(12) =2071a(13) =2380a(14) =2716a(15) =3080a(16) =3473a(17) =3896a(18) =4350a(19) =4836a(20) =5355a(21) =5908a(22) =6496a(23) =7120a(24) =7781a(25) =8480a(26) =9218a(27) =9996a(28) =10815a(29) =11676