a(n) = 49*n^2 - n.

Terms

a(0) =48a(1) =194a(2) =438a(3) =780a(4) =1220a(5) =1758a(6) =2394a(7) =3128a(8) =3960a(9) =4890a(10) =5918a(11) =7044a(12) =8268a(13) =9590a(14) =11010a(15) =12528a(16) =14144a(17) =15858a(18) =17670a(19) =19580a(20) =21588a(21) =23694a(22) =25898a(23) =28200a(24) =30600a(25) =33098a(26) =35694a(27) =38388a(28) =41180a(29) =44070