YaCoin (YAC) was created in May 2013 - so not one of the later 2013 deluge of currencies. It was also the first coin to introduce the Scypt-n parameter. Reward is equal to 25 divided by the difficulty to the power of 1/6. The coin is a hybrid proof of work and proof of stake coin with a fixed transaction fee of 0.01 YAC per transaction. The coin is a dynamic inflationary/deflationary economic model - like peercoin - as the block rewards for POW mining are inversely proportional to the amount of computer power used. The Proof of stake is set at 5% per annum. The fixed transaction fee will act as a brake to supply depending on the velocity of it use - i.e. how much it is used - probably one of the most innovative economic models out there.