Can we reduce Fermat last theorem problem to the case $z=x+1$ where $x^n + y^n = z^n$?
Why am I asking that? I found in that case and in case $n=3$ that difference of cubes: $1$,$7$,$19$,$37$ http://oeis.org/A003215
is a combination of diferrence of next sequence: http://oeis.org/A011934