TY  - JOUR
AB  - Let n > 2 be a positive integer and let ? denote Euler's totient function. Define ?1(n) = ?(n) and ?k(n) = ?(?k-1(n)) for all integers k ? 2. Define the arithmetic function S by S(n) = ?(n) + ?2(n) +...+ ?c(n) + 1, where ?c(n) = 2. We say n is a perfect totient number if S(n) = n. We give a list of known perfect totient numbers, and we give sufficient conditions for the existence of further perfect totient numbers.
AU  - Iannucci, DE
AU  - Moujie, D
AU  - Cohen, GL
DA  - 2003/12/01
JO  - Journal of Integer Sequences
PY  - 2003/12/01
TI  - On perfect totient numbers
VL  - 6
Y1  - 2003/12/01
Y2  - 2026/05/01
ER  -