User blog comment:Xxmarijnw/Wezel's Number/@comment-25601061-20141211023557

Ok:

↨ = (10^10^100)^^(10^10^100)

↨↨ = ((10^10^100)^^(10^10^100))^^((10^10^100)^^(10^10^100))

etc.

Around 10^^^(10^10^10^100).