program phuongt; uses crt; var n, i, k, s: integer; begin clrscr; write('Nhap n = '); readln(n); k:=2*n+1; for i:=1 to k do if i mod 2 <> 0 then s:=s+i; write('s = ', s); readln end.
uses crt; var i,n,s:longint; begin clrscr; write('Nhap n: ');readln(n); i:=-1; s:=0; while i<2*n+1 do begin inc(i,2); s:=s+i; end; writeln('s= ',s); readln end.
