Geodesic
The 4-Nicol numbers having five different prime divisors
Journal of integer sequences, Tome 14 (2011) no. 7
A positive integer $ n$ is called a Nicol number if $ n\mid \varphi(n)+\sigma(n)$, and a $t$-Nicol number if $ \varphi(n)+\sigma(n)=tn$. In this paper, we show that if $ n$ is a 4-Nicol number that has five different prime divisors, then $ n=2^{\alpha_{1}}\cdot 3\cdot 5^{\alpha_{3}}\cdot p^{\alpha_{4}}\cdot q^{\alpha_{5}}$, or $ n=2^{\alpha_{1}}\cdot 3\cdot 7^{\alpha_{3}}\cdot p^{\alpha_{4}}\cdot q^{\alpha_{5}}$ with $ p\leq 29$.
Classification : 11A25
Keywords: nicol number, Euler's totient function 
@article{JIS_2011__14_7_a6,
     author = {Jin,  Qiao-Xiao and Tang,  Min},
     title = {The {4-Nicol} numbers having five different prime divisors},
     journal = {Journal of integer sequences},
     year = {2011},
     volume = {14},
     number = {7},
     zbl = {1223.11006},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2011__14_7_a6/}
}
TY  - JOUR
AU  - Jin,  Qiao-Xiao
AU  - Tang,  Min
TI  - The 4-Nicol numbers having five different prime divisors
JO  - Journal of integer sequences
PY  - 2011
VL  - 14
IS  - 7
UR  - http://geodesic.mathdoc.fr/item/JIS_2011__14_7_a6/
LA  - en
ID  - JIS_2011__14_7_a6
ER  - 
%0 Journal Article
%A Jin,  Qiao-Xiao
%A Tang,  Min
%T The 4-Nicol numbers having five different prime divisors
%J Journal of integer sequences
%D 2011
%V 14
%N 7
%U http://geodesic.mathdoc.fr/item/JIS_2011__14_7_a6/
%G en
%F JIS_2011__14_7_a6
Jin,  Qiao-Xiao; Tang,  Min. The 4-Nicol numbers having five different prime divisors. Journal of integer sequences, Tome 14 (2011) no. 7. http://geodesic.mathdoc.fr/item/JIS_2011__14_7_a6/