Ikegami, thanks a ton for the comments!

I designed this script for testing where I wanted to use contiguous MAC addresses on a traffic generator. To give it an easy naming convention, I based it on a decimal for a subnet feel. I had intended to print the start value into a hex/MAC format, and then increment from there.
My solution for the one-off error will be to not include the start value as an increment iteration.

Any ideas on how to correct the conversion beyond 17179869184. I'm not sure
how to fix this one.

Again, I greatly appreciate the feedback!!!