%I #13 Nov 04 2019 00:57:59

%S 1,2,6,10,12,15,18,20,21,22,24,26,28,30,33,35,36,38,40,42,44,45,48,50,

%T 51,52,54,56,57,58,60,63,66,69,70,72,74,75,76,77,78,80,84,85,87,88,90,

%U 91,92,93,96,99,100,102,104,105,106,108,110,114,115,116,118,119,120,122

%N Numbers k such that A328925(k) = 1; numbers k such that if we write k = Product_{i=1..t} p_i^e_i, then lcm_{1<=i,j<=t,i!=j} ord(p_i,p_j^e_j) = A002322(k), where ord(a,r) is the multiplicative order of a modulo r, and A002322 is the Carmichael lambda (usually written as psi).

%C Numbers such that A118106(k) = A002322(k).

%C {a(n)} intersect A000961 = {1, 2}.

%C {a(n)} union A329062 = N* \ A000961 U {1, 2}.

%C If k = Product_{i=1..t} p_i^e_i (t > 1), where {p_i} are primes such that p_i is a lambda primitive root modulo p_j^e_j for all i != j (that is to say, ord(p_i,p_j^e_j) = A002322(p_j^e_j), where ord(a,r) is the multiplicative order of a modulo r), then k is here, as A118106(k) = A002322(k). For example, k = 2^5 * 5 * 13.

%e For k = 115 = 5 * 23, A118106(115) = lcm(ord(23,5),ord(5,23)) = lcm(4,22) = 44 = A002322(115), so 115 is a term.

%e For k = 973 = 7 * 139, A118106(973) = lcm(ord(139,7),ord(7,139)) = lcm(6,69) = 138 = A002322(973), so 973 is a term.

%o (PARI) isA328926(n) = (A002322(n) == A118106(n)) \\ See A002322 and A118106 for their programs

%Y Cf. A118106, A002322, A326925, A329062, A000961.

%K nonn

%O 1,2

%A _Jianing Song_, Oct 31 2019