User blog comment:SuperSpruce/The T array function/@comment-38080588-20190221190022/@comment-36984051-20190221200201

T_(n+1)[0]=(n+1)+1=n+2.

The subscript here is like the input n of the FGH f_α(n).

An example here would be... T_3[1] =T_(T_(T_3[0])[0])[0] =T_(T_(3+1)[0])[0] =T_(T_4[0])[0] =T_(4+1)[0] =T_5[0] =5+1 =6