srw
It's a bit more complicated than that...
Obviously if the country is small enough (San Marino, Lichtenstein, Monaco, Vatican, Andorra, Hong Kong, Singapore), it's a triviality to see a foreign country from the capital - and since most of those are built up their capitals also border abroad. And in some sense a country's embassy is sovereign territory of the country, so most capital cities border "abroad".
It's possible to see all the channel islands from France, so I'd assume the reverse is true - but not necessarily from their capitals (to the extent that they are independent nations).
It's possible to see all the channel islands from France, so I'd assume the reverse is true - but not necessarily from their capitals (to the extent that they are independent nations).