I interpreted it as creating the controlflow graph based only on the existence of jump commands, so it does not depend on values of a and b. Actual behavior of the program will depend on those, but the graph won't.
I believe the sequence 0, 2, 2, ... starts from 1 for path length (that's another kindofflaw in the problem description, as it links to an OEIS sequence with a definition that doesn't match, without mentioning that you need a different offset). The 0 means that there is no direct path from the starting node in the graph to the end node, then 2 means there are 2 possible paths with 2 steps.
