[lmikle]

Вот так проще:

Код:

program Test;

{$APPTYPE CONSOLE}

var
  D, I, S : Integer;
begin
  write('Input N='); readln(N);
  
  S := 0;
  for I := 0 To N Do
    S := S + sqr(N+I);

  writeln('Sum=',S);
end.