OFFSET
1,6
COMMENTS
REFERENCES
R. K. Guy, Unsolved Problems in Number Theory, A17.
LINKS
Ivan Neretin, Table of n, a(n) for n = 1..10000
FORMULA
a(prime) = 0 and a(4n) = 1.
a(n) == A204187(n) + 1 (mod n).
EXAMPLE
Sum(m^3, m=1..3) + 1 = 1^3 + 2^3 + 3^3 + 1 = 37 == 1 (mod 4), so a(4) = 1.
MATHEMATICA
Table[Mod[Plus @@ PowerMod[Range[n - 1], n - 1, n] + 1, n], {n, 77}] (* Ivan Neretin, Sep 23 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Jonathan Sondow, Jan 11 2012
STATUS
approved