|
%I #6 Dec 21 2014 07:49:06
%S 0,5,16,38,47,40,66,84,150,33,72,10,106,178,168,140,265,54,534,106,68,
%T 20,296,56,564,231,732,52,730,26,604,114,80,164,348,332,297,50,912,84,
%U 904,110,88,130,222,552,332,76,1430,81,702,236,950,178,256,168,564
%N a(n) = |{m : multiplicative order of n mod m = 10}|.
%H Alois P. Heinz, <a href="/A218259/b218259.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = tau(n^10-1)-tau(n^5-1)-tau(n^2-1)+tau(n-1), with tau = A000005.
%p with(numtheory):
%p a:= n-> add(mobius(10/d) *tau(n^d-1), d={1, 2, 5, 10}):
%p seq(a(n), n=1..80);
%Y Row n=10 of A212957.
%Y Cf. A000005, A008683.
%K nonn
%O 1,2
%A _Alois P. Heinz_, Oct 24 2012
|
