Maybe I am missing something, but if we have shown that 1 is a power of 2, and for some natural number k=>1, we are assuming k is a sum of powers of 2, wouldn't k+1 necessarily be of the correct form since we are adding a power of two to a finite sum of powers of two we are left with a finite...
Why not try looking at a circle of radius one centered at the origin, counting the points of interest there? Then look at a circle of radius 2 centered the origin, and count those points. Then a circle with radius 3, a circle with radius 4, radius 5, ..., radius n, and maybe you will be able to...
It is stated in almost every linear algebra text i could find that the inverse of a triangular matrix is also triangular, but no proofs accompanied such statements.
I am convinced that it is the truth, but I have not been able to write anything down that I am satisfied with that doesn't rely...
you could draw a quadrant of a circle of radius 6 and check the number of points there and multiply that number by four, being careful not to double count points that lie on the axis,
as for a closed form, i would be surprised if one did not exist...
Side note
Wolfram indeed does have a...
Maybe our definitions of convolutions are different, but the definition I have learned for the convolution of two functions is defined by an integral, i.e. $ f*g(t)=\int_{0}^{t}f(u)g(t-u)du.$ Letting $v=t-u,$ then $dv=-du$($t$ is constant with respect to $u$). We also need to change our limits...