Question 934972
{{{4=2^2}}}, {{{256=2^8}}}.



{{{a[3]}}},{{{a[3]*r}}},{{{a[3]*r^2}}},{{{a[4]*r^3}}}


Sixth term is {{{4*r^3=256}}}
{{{r^3=64}}}
{{{r^3=(2^3)^2}}}
{{{r^3=2^6}}}
{{{highlight_green(r=4)}}}.


Work backward using that common ratio from term at index 3 to term at index 1.
{{{4/4=1}}};
{{{1/4=1/4}}}------------the term, {{{a[1]}}}.


General term for the sequence is  {{{highlight((1/4)^(n-1))}}}.