a(n) = n*(23*n - 1)/2.

Terms

a(0) =0a(1) =11a(2) =45a(3) =102a(4) =182a(5) =285a(6) =411a(7) =560a(8) =732a(9) =927a(10) =1145a(11) =1386a(12) =1650a(13) =1937a(14) =2247a(15) =2580a(16) =2936a(17) =3315a(18) =3717a(19) =4142a(20) =4590a(21) =5061a(22) =5555a(23) =6072a(24) =6612a(25) =7175a(26) =7761a(27) =8370a(28) =9002a(29) =9657