In addition, Graham (1964) constructed a pair of numbers (one 33 digits and the other 34)
(2)
(3)
satisfying this condition. Knuth (1990) subsequently found a 17-digit pair
(4)
(5)
satisfying the same conditions. Almost immediately, Wilf (1990) found a smaller pair (one 17 digits and the other 16)
(6)
(7)
Note that Hoffman (1998, p. 159) inadvertently inverted the order of the Wilf (1990) pair, thus obtaining a sequence that has prime terms for , 163, 190, 523, 1855, 3228, 3579, 6468, 7170, 10230, 12783,
17259, 60139, 91315, 97923, 101823, 156075, 182220, ... (OEIS A108156),
with no others for
(E. W. Weisstein, May 5, 2006).
Nicol (1999) subsequently found the 12-digit pair .