OFFSET
1,1
COMMENTS
Numbers with five or more divisors. - Lekraj Beedassy, Sep 11 2003
Called multiplicatively abundant numbers by Chau (2004). - Amiram Eldar, Jun 29 2022
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
William Chau, The tau, sigma, rho functions, and some related numbers, Pi Mu Epsilon Journal, Vol. 11, No. 10 (Spring 2004), pp. 519-534; entire issue.
FORMULA
The number of terms not exceeding x is N(x) ~ x*(1 - log(log(x))/log(x)) (Chau, 2004). - Amiram Eldar, Jun 29 2022
MATHEMATICA
Select[Range[150], #^(DivisorSigma[0, #]/2) > #^2 &] (* Amiram Eldar, Jun 29 2022 *)
Select[Range[200], Times@@Divisors[#]>#^2&] (* Harvey P. Dale, Oct 20 2024 *)
PROG
(PARI) is(n)=numdiv(n)>4 \\ Charles R Greathouse IV, Sep 18 2015
(Python)
from sympy import divisor_count
def ok(n): return divisor_count(n) > 4
print([k for k in range(148) if ok(k)]) # Michael S. Branicky, Dec 16 2021
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
N. J. A. Sloane, Nov 24 2000
STATUS
approved