In 1975 F. Cohen and J.L. Selfridge found a 94-digit positive integer which cannot be written as the sum or difference of two prime powers. Following their basic construction and introducing a new method to avoid a bunch of extra congruences, we are able to prove that if
x
≡
47867742232066880047611079
(
mod
66483034025018711639862527490
)
,
\begin{equation*} \hspace {-1.5pc} x\equiv 47867742232066880047611079 (\operatorname {mod} 66483034025018711639862527490), \hspace {-1.5pc} \end{equation*}
then
x
x
is not of the form
±
p
a
±
q
b
\pm p^{a}\pm q^{b}
where
p
,
q
p,q
are primes and
a
,
b
a,b
are nonnegative integers.