for i := 2 to n do
  begin
    a[i] := a[i - 1] * 5;
    for j := i div 5 to i - 1 do
    begin
    if (a[j] * 2 > a[i - 1]) and (a[j] * 2 < a[i]) then
      a[i] := a[j] * 2;
    if (a[j] * 3 > a[i - 1]) and (a[j] * 3 < a[i]) then
      a[i] := a[j] * 3;
    if (a[j] * 5 > a[i - 1]) and (a[j] * 5 < a[i]) then
      a[i] := a[j] * 5;
    end;
  end;