uses crt;
var n,i : integer;
s : longint;
begin
s:=1999;
write('Nhap n:'); readln(n);
s:=s+(n+1)*(n+1);
write(s);
readln
end.
Hoặc :
uses crt;
var n,i : integer;
s : longint;
begin
s:=1999;
write('Nhap n:'); readln(n);
for i:=1 to 2*n+1 do if i mod 2 = 1 then s:=s+i;
write(s);
readln
end.