Link to address:
https://rain.acc-pool.pw/address/RSEmiSifB1wSnYXf3132dAjFvbs1ABsJ4R
Amount 20038160.00000000 RAIN
Even the 38160 RAIN I mined afterwards are stuck in there, LOL
The only option I can think of is to post the address publicly so everyone could see that I haven't moved them...
...but that would still require everyone to actually trust me here
have a look here at Community Coin,
they hardcoded to reject any transactions from a particular address,
locking those coins away for ever !!! even if someone found the lost wallet
https://github.com/communitycoin/communitycoin/blob/master/src/main.cpp#L306
Community Coin had a different motivation, they banned a huge amount of coins to prevent a select few individuals from manipulating the coin price. If I understand correctly you want to reduce the supply to make a coin more valuable therefore it might not be necessary to lock such a big amount. Just send a chunk of the premine to a non-spendable address and you are good to go.