|
%I #16 Aug 31 2020 02:40:08
%S 1,3,5,7,9,11,13,17,19,21,23,25,27,28,29,31,33,36,37,41,43,44,47,49,
%T 53,56,57,59,61,63,65,67,69,71,72,73,76,77,79,81,83,84,88,89,92,93,97,
%U 99,101,103,107,108,109,113,121,124,125,127,129,131,132,133
%N Numbers k such that 1^(lambda(k)/2) + 2^(lambda(k)/2) + ... + (k - 1)^(lambda(k)/2) = 0 (mod k), where lambda is the Carmichael reduced totient function.
%C Conjecture: The asymptotic density is zero.
%H Amiram Eldar, <a href="/A200982/b200982.txt">Table of n, a(n) for n = 1..10000</a>
%t Select[Range[200], (Mod[Sum[PowerMod[j, CarmichaelLambda[#]/2, #], {j, #}], #] == 0) &]
%Y Cf. A002322 (the reduced totient function).
%K nonn
%O 1,2
%A _José María Grau Ribas_, Nov 25 2011
|
