Don't you mean

[LaTeX ERROR: Convert failed]

or

[LaTeX ERROR: Convert failed]

These two results follow directly from the application of the binomial theorem in reverse.

[LaTeX ERROR: Convert failed]

with x = 1 and y = 2 where in the second one we are subtracting 1 since we are not summing over the first term which is [LaTeX ERROR: Convert failed]

EDIT: Here is the second one:

[LaTeX ERROR: Convert failed]

[LaTeX ERROR: Convert failed]

Now the sum becomes:

[LaTeX ERROR: Convert failed]