4*(n + 7)^3 - 27*(n + 7)^2 = (4*n +1)*(n+7)^2.

Terms

a(0) =49a(1) =320a(2) =729a(3) =1300a(4) =2057a(5) =3024a(6) =4225a(7) =5684a(8) =7425a(9) =9472a(10) =11849a(11) =14580a(12) =17689a(13) =21200a(14) =25137a(15) =29524a(16) =34385a(17) =39744a(18) =45625a(19) =52052a(20) =59049a(21) =66640a(22) =74849a(23) =83700a(24) =93217a(25) =103424a(26) =114345a(27) =126004a(28) =138425a(29) =151632