i think so,
because consider 7^(k)=(9Q+1)/(3k+1)
let k = n+1
thus 7^(n+1)=(9Q+1)/(3(n+1)+1)=7^(n+1)=(9Q+1)/(3n+4)
just swap n bak to k - theya re both dummy variables
if you dont like it, just change 7^(k+1) into 7.7^k, and sub in the statement for 7^k bak in, and youll just...