OFFSET
1,1
COMMENTS
Always an integer: for an elementary proof that Sum(m^k,m=1..p-1)/p is an integer if p is prime and p-1 does not divide k (and a discussion of other proofs), see MacMillan and Sondow 2011. Applications are in Sondow and MacMillan 2011.
For (Sum(m^(p-1), m=1..p-1)+1)/p as p runs through the primes, see A055030.
For Sum(m^p, m=1..p-1) / p^2 as p runs through the odd primes, see A294507.
LINKS
K. MacMillan and J. Sondow, Proofs of power sum and binomial coefficient congruences via Pascal's identity, Amer. Math. Monthly, 118 (2011), 549-551.
J. Sondow and K. MacMillan, Reducing the Erdos-Moser equation 1^n + 2^n + ... + k^n = (k+1)^n modulo k and k^2, Integers 11 (2011), #A34.
EXAMPLE
a(1) = (1^3 + 2^3)/3 = (1 + 8)/3 = 3.
MATHEMATICA
Array[Sum[m^#, {m, # - 1}]/# &@ Prime@ # &, 11, 2] (* Michael De Vlieger, Nov 04 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Jonathan Sondow, Dec 04 2012
STATUS
approved