Nearest integer to 4*Pi*n^2.

Terms

a(0) =0a(1) =13a(2) =50a(3) =113a(4) =201a(5) =314a(6) =452a(7) =616a(8) =804a(9) =1018a(10) =1257a(11) =1521a(12) =1810a(13) =2124a(14) =2463a(15) =2827a(16) =3217a(17) =3632a(18) =4072a(19) =4536a(20) =5027a(21) =5542a(22) =6082a(23) =6648a(24) =7238a(25) =7854a(26) =8495a(27) =9161a(28) =9852a(29) =10568