OFFSET
1,1
COMMENTS
Catalan's conjecture (now a theorem) is that 1 occurs just once as a difference, between 8 and 9.
REFERENCES
G. Everest, A. van der Poorten, I. Shparlinski and T. Ward, Recurrence Sequences, Amer. Math. Soc., 2003; see esp. p. 255.
LINKS
Robert G. Wilson v, Table of n, a(n) for n = 1..4479
Alf van der Poorten, Remarks on the sequence of 'perfect' powers.
MATHEMATICA
pp = Union[ Join[{1}, Flatten[ Table[n^i, {n, 2, Sqrt[10^12]}, {i, 2, Log[n, 10^12]}]]]]; l = Length[pp]; d = Sort[Take[pp, -l + 1] - Take[pp, l - 1]]; Complement[ Table[i, {i, 1, 200}], Take[ Union[d], 200]] (* Robert G. Wilson v *)
CROSSREFS
KEYWORD
nonn,nice
AUTHOR
STATUS
approved