a=Import["/tmp/test.dat"];

Show[ListPlot[a[[-10;;]],Joined->True]]

1-14/(16-1)//N

Solve[((T[i+1]-T[i])η[i]+sumBelow)/(sumAbove+(T[i+2]-T[i+1])η[i+1]+(T[i+1]-T[i])η[i]+sumBelow)==cc,T[i+1]]//Simplify

Sum[(T[j+1]-T[j])[j],{j,1,i}]==(i+1)