User blog comment:Wythagoras/Strength of Hierarchical Nested Subscript Array Notation/@comment-11227630-20130926102307/@comment-11227630-20130927103657

It's Nested-subscript array notation (not hierarchical) and can only reach θ(θ1(Ω)) there in that page. In another word, if you want to reach weakly Mahlo cardinal, you cannot use NSAN or HHNAN only, and you must use new rules.