a(n) = 10*n^3 - 6*n^2.

Terms

a(0) =0a(1) =4a(2) =56a(3) =216a(4) =544a(5) =1100a(6) =1944a(7) =3136a(8) =4736a(9) =6804a(10) =9400a(11) =12584a(12) =16416a(13) =20956a(14) =26264a(15) =32400a(16) =39424a(17) =47396a(18) =56376a(19) =66424a(20) =77600a(21) =89964a(22) =103576a(23) =118496a(24) =134784a(25) =152500a(26) =171704a(27) =192456a(28) =214816a(29) =238844