Are you trying to find a solution for one of the available work items on old Vanity Pool: https://vanitypool.appspot.com/availableWork? C'mon how lame is that!?

If you want the claim the payout (not really sure if it's actually still possible) you have to find a solution that works with the split key technique there. You can't just provide any solution. This is not how split key vanity pool works.