a(n) = 14*n^2.

Terms

a(0) =0a(1) =14a(2) =56a(3) =126a(4) =224a(5) =350a(6) =504a(7) =686a(8) =896a(9) =1134a(10) =1400a(11) =1694a(12) =2016a(13) =2366a(14) =2744a(15) =3150a(16) =3584a(17) =4046a(18) =4536a(19) =5054a(20) =5600a(21) =6174a(22) =6776a(23) =7406a(24) =8064a(25) =8750a(26) =9464a(27) =10206a(28) =10976a(29) =11774