User blog comment:Billybob-mario/Hyperrecursion of Uncomputable Functions/@comment-4224897-20150427222636/@comment-173.76.204.173-20150429002629

It's not just FOOT + arrow iteration, which people seem to be ignoring. It's that ANY function can be iterated with ANY iterative system. Maybe that isn't the most original idea, but the concept is more interesting than a single combination. FOOT + BEAF is, as far as I am aware, the combination of currently-used systems that would result in the largest number.