I may have got confused, or misread some
recent messages, but am I right in
thinking that
Sierpi'nski numbers are values of k
such that
k * 2^n + 1
is composite for all n and
Riesel numbers are values of k
such that
k * 2^n - 1
is composite for all n ??
Sierpi'nski worked on the former
when Riesel must have been quite
a little boy. R.