Question 904108
The rule is what is done to the input to produce the output.


Not required to be easy, but I believe I detect something:


{{{1/3=(1^2)/3}}};


{{{4/3=(2^2)/3}}};


{{{3=9/3=(3^2)/3}}}...



The NUMERATOR of the term at index n is n^2, but you are including a term of index 0 to begin.  Each output then is {{{(n^2)/3}}}, for each input of index n.