Following is a list of special combination keys you can use to create letters or characters with accents. You can create the following characters by holding the ALT key and entering the corresponding numbers using the number keypad.

NOTE: Do not use the number row above the letter keys.

á 160          ä 132  
é130 ë 137
í161  ï139
ó162 ö 148
ú 163  ü 129
ñ 164  å 134
Ñ 165  â 131
à 133  ê 136
è 138  î 140
ì 141  ô 147
ò 149  ù 151
û 150  ç 135

You can find a full list of ALT + number codes here