Melody,
First I want to say thank you very much, you have helped me see the numerators as powers of 3.
I did some aditional study on the net, and came to this conclusion:
The numerators change to:
30;31;32;33
so this has to be :
3n−1 = NOMINATOR
which I understand...THEN:
you subtracted the denominators and found:
5;8;13;20
becomes: 3;5;7;9
which becomes: 2;2;2
From this we see that: 2a=2, therefore, a=1
3a+b = 3, therefore "b" calculates to 0
and a+b+c=T1=5, so "c" calculates to 4
The general equation is: an2+bn+c
So substitute everything above into this equation, and it calculates to n2+4 = DENOMINATOR
So that is then NominatorDenominator=3n−1n2+4
thank you kindly for your help Melody!!