a(n) = 7*n^2.

Terms

a(0) =0a(1) =7a(2) =28a(3) =63a(4) =112a(5) =175a(6) =252a(7) =343a(8) =448a(9) =567a(10) =700a(11) =847a(12) =1008a(13) =1183a(14) =1372a(15) =1575a(16) =1792a(17) =2023a(18) =2268a(19) =2527a(20) =2800a(21) =3087a(22) =3388a(23) =3703a(24) =4032a(25) =4375a(26) =4732a(27) =5103a(28) =5488a(29) =5887