Proof of Usefulness?

[Euro1000]

Bitcoin (and other altcoins) spends huge amounts of electricity just to solve a riddle. The result is (beside the creation of the block) not useful at all.
Is there any altcoin/token where the "miners" have to compute something which has any kind of use? Perhaps calculating prime numbers or sequencing a genom or verify something?

Perhaps I am totally wrong and this is not possible - perhaps there is already somehting implemented like this ...