Thanks, this is the right level of mathematics needed :-)
Sorry I hadn't seen this before.

One question: why do recent steemitblog posts mention 20 STEEM as a kind of pivot point for earning more/less between HF20 and HF21?

the last time I looked on github, the chosen reward curve parameter was 2e11. has that been changed?
I see you use 2e12.
Maybe the quoted 20 STEEM is not quite the pivot point.

Would appreciate a reply. Thanks.