a(n) = dot_product(1,2,...,n)*(3,4,...,n,1,2).

Terms

a(0) =11a(1) =22a(2) =40a(3) =67a(4) =105a(5) =156a(6) =222a(7) =305a(8) =407a(9) =530a(10) =676a(11) =847a(12) =1045a(13) =1272a(14) =1530a(15) =1821a(16) =2147a(17) =2510a(18) =2912a(19) =3355a(20) =3841a(21) =4372a(22) =4950a(23) =5577a(24) =6255a(25) =6986a(26) =7772a(27) =8615a(28) =9517a(29) =10480