a(n) = n*(n+1)*(5*n+1)/3.

Terms

a(0) =0a(1) =4a(2) =22a(3) =64a(4) =140a(5) =260a(6) =434a(7) =672a(8) =984a(9) =1380a(10) =1870a(11) =2464a(12) =3172a(13) =4004a(14) =4970a(15) =6080a(16) =7344a(17) =8772a(18) =10374a(19) =12160a(20) =14140a(21) =16324a(22) =18722a(23) =21344a(24) =24200a(25) =27300a(26) =30654a(27) =34272a(28) =38164a(29) =42340