给出了形如3kp(k≥1,p为奇素数)的数为完全欧拉数的一般判别法,指出目前已知的所有判别法都是它的推论,并且发现Iannucci等人给出的6个判别法有4个是无用的.
Let n〉2 be a positive integer and let ф denote Euler's totient function.Define ф1(n)=ф(n) and фk(n)=ф(фk-1(n)) for all integer k≥2.Define the arithmetic function S by S(n)=ф(n)+ф2(n)+…+фc(n)+1,where фc(n)=2.An integer n is called a perfect totient number if S(n)=n.A general sufficient condition is given for the existence of the prefect totient numbers of the form 3kp for k≥1 where p is an odd prime.Furthermore,theorem 1:(2),(3),theorem 2 and theorem 3 in Inannucci et al.are of no effect.