cp's OEIS Frontend

A205551 The least j such that n divides k^k-j^j, where k (as in A205546) is the least number for which there is such a j.

%I A205551 #6 Dec 04 2016 19:46:26
%S A205551 1,1,1,2,1,2,2,4,2,4,1,2,1,2,1,4,1,2,4,4,2,1,2,4,4,1,3,2,4,4,1,4,3,4,
%T A205551 1,2,4,1,1,4,5,2,1,1,1,2,4,4,6,4,1,1,7,3,6,6,7,4,5,4,5,2,2,4,1,3,6,4,
%U A205551 2,6,1,8,3,1,6,1,6,3,8,4,6,5,12,2,1,4,1,6,2,6,1,2,9,4,5,4,6,6,3
%N A205551 The least j such that n divides k^k-j^j, where k (as in A205546) is the least number for which there is such a j.
%C A205551 For a guide to related sequences, see A204892.
%e A205551 1 divides 2^2-1^1 -> k=2, j=1
%e A205551 2 divides 3^3-1^1 -> k=3, j=1
%e A205551 3 divides 2^2-1^1 -> k=2, j=1
%e A205551 4 divides 4^4-2^2 -> k=2, j=2
%t A205551 s = Table[n^n, {n, 1, 120}];
%t A205551 lk = Table[NestWhile[# + 1 &, 1,
%t A205551    Min[Table[Mod[s[[#]] - s[[j]], z], {j, 1, # - 1}]] =!= 0 &], {z, 1, Length[s]}]
%t A205551 Table[NestWhile[# + 1 &, 1,
%t A205551   Mod[s[[lk[[j]]]] - s[[#]], j] =!= 0 &],
%t A205551  {j, 1, Length[lk]}]
%t A205551 (* _Peter J. C. Moses_, Jan 27 2012 *)
%Y A205551 Cf. A204892.
%K A205551 nonn
%O A205551 1,4
%A A205551 _Clark Kimberling_, Jan 31 2012