User blog comment:Unknown95387/Help please/@comment-30754445-20171126162320/@comment-30754445-20171126175407

It's actually 61 rather than 64, but that's my fault rather than yours. I've got the knuth arrows expression wrong. It should have been:

Ackerman(n,n) = 2 [n-2 arrows] (n+3) - 3 (note the "2")

So:

mag(3) = [(2↑5964) - 3 ]↑[(2↑ 5964) - 5] (2↑5964) - 3 ≈ fω(2↑5964) '≈ fω(f60(61))'