There is no specific combination. Some keypad numbers play a note, some of them play short melodies
oh I see, I thought there was some puzzle to it and gave up xD
It's a good idea. If it came to my mind, i would do that.
I thought the word "alphabet" is the puzzle and tried to convert the letters to numbers (a=1, l=12 ...)
SInce it's a little puzzle game some fun thing like that could be worth adding