a(n) = 62*n^2 - 1.

Terms

a(0) =61a(1) =247a(2) =557a(3) =991a(4) =1549a(5) =2231a(6) =3037a(7) =3967a(8) =5021a(9) =6199a(10) =7501a(11) =8927a(12) =10477a(13) =12151a(14) =13949a(15) =15871a(16) =17917a(17) =20087a(18) =22381a(19) =24799a(20) =27341a(21) =30007a(22) =32797a(23) =35711a(24) =38749a(25) =41911a(26) =45197a(27) =48607a(28) =52141a(29) =55799