The Stronger Feit-Thompson conjecture states that:
There exist no distinct prime numbers $p$ and $q$ such that: $\dfrac {p^q - 1} {p - 1}$ and $\dfrac {q^p - 1} {q - 1}$ are not coprime.
This was refuted by N.M. Stephens in July 1971 who published On the Feit-Thompson Conjecture in Mathematics of Computation volume 25 no. 115 (p. 625) where he showed that for $p = 17$ and $q = 3313$, the above expressions have the common prime factor $112 \, 643$.
The Wikipedia article Feit–Thompson conjecture suggests his first name might have been Nelson, but I have been unable to corroborate this.
Does anyone have any biographical details about N.M. Stephens?