

A000445


Latest possible occurrence of the first consecutive pair of nth power residues, modulo any prime.
(Formerly M4652 N1991)


5




OFFSET

2,1


COMMENTS

The paper by Adolf Hildebrand proves that a(n) is finite for all n.  Christopher E. Thompson, Dec 05 2019
Don Reble has reported computations proving that 1499876 <= a(8) <= 1508324, which improves on the references below. Note also that it shows a(8) < a(7).  Christopher E. Thompson, Jan 14 2020


REFERENCES

P. Erdős and R. L. Graham, Old and New Problems and Results in Combinatorial Number Theory. L'Enseignement Math., Geneva, 1980, p. 87.
W. H. Mills, Bounded consecutive residues and related problems, pp. 170174 of A. L. Whiteman, ed., Theory of Numbers, Proc. Sympos. Pure Math., 8 (1965). Amer. Math. Soc.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS

Table of n, a(n) for n=2..7.
R. G. Bierstedt, W. H. Mills, On the bound for a pair of consecutive quartic residues of a prime, Proc. Amer. Math. Soc. 14, 628632 (1963).
J. Brillhart, D. H. Lehmer and E. Lehmer, Bounds for pairs of consecutive seventh and higher power residues, Math. Comp. 18 (1964), 397407.
M. Dunton, Bounds for Pairs of Cubic Residues, Proc. Amer. Math. Soc. 16 (1965), 330332.
Adolf Hildebrand, On consecutive kth power residues. II., Michigan Math. J., 38 (1991), no. 2, 241253.
J. H. Jordan, Pairs of consecutive power residues or nonresidues, Canad. J. Math., 16 (1964), 310314.
J. R. Rabung and J. H. Jordan, Consecutive power residues or nonresidues, Math. Comp. 24 (1970), 737740.
Don Reble, More terms for A000445?, posting to SeqFan mailing list, Dec 19 2019.


EXAMPLE

Every large prime has a pair of consecutive quadratic (n=2) residues which appear not later than 9,10, so a(2)=9.  Len Smiley


CROSSREFS

Cf. A000236.
Sequence in context: A355372 A046150 A124131 * A046196 A231596 A350428
Adjacent sequences: A000442 A000443 A000444 * A000446 A000447 A000448


KEYWORD

nonn,nice,more,hard


AUTHOR

N. J. A. Sloane


EXTENSIONS

Name edited by Christopher E. Thompson, Dec 10 2019


STATUS

approved



