So this is how chained arrow notation works for 4 entries: a->b->c->1=a^^^^^...^^^^^b (see my hyperoperation project), a->b->1->d=a^b a->b->c->d=a->b->(a->b->(c-1)->d)->d-1 Extended notation here http://googology.wikia.com/wiki/Chained_arrow_notation
