OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
F. Luca, On the product of divisors of n and sigma(n), J. Inequal. Pure Appl. Math., Volume 4, Issue 2, Article 46, 2003.
MATHEMATICA
Select[Range[1000], Times @@ Divisors[#] > Times @@ Divisors[DivisorSigma[1, #]] &] (* T. D. Noe, Nov 19 2012 *)
PROG
(PARI) A007955(n)=if(issquare(n, &n), n^numdiv(n^2), n^(numdiv(n)/2))
(Python)
from math import isqrt
from itertools import count, islice
from sympy import divisor_count, divisor_sigma
def A219364_gen(): # generator of terms
return filter(lambda n: (f:=(lambda m:isqrt(m)**c if (c:=divisor_count(m)) & 1 else m**(c//2)))(n) > f(divisor_sigma(n)), count(1))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Michel Marcus, Nov 19 2012
STATUS
approved