[pesi]

Код:

const
  bk = 'ABCDE';
var
  I1, I2: Integer;
begin
  Memo1.Text:= bk;
  for I1:=1 to 5 do
    Memo1.Lines.Add(bk[I1]);
  for I1:= 1 to 5 do
  for I2:= 2 to 5 do
    if (I1<>I2) and (I1<I2) then
      Memo1.Lines.Add(bk[I1]+bk[I2]);
end;