User blog comment:Alejandro Magno/Make an extension of the notation remake 2/@comment-5029411-20141022235015

a[n,(x,y),m] = a[n,(a[n,(...a[n,(a[n,(a,y-1),m],y-1),m]...,y-1),m],y-1),m] with x levels

a[n,(x,,y),m] = a[n,(x,x,x,...,x,x,x),m] with y x's

a[n,(x,(1),y),m] = a[n,(x,,,...,,,x),m] with y commas