cp's OEIS Frontend

A366757 a(n) is the sum of the divisors of n!-1.

%I A366757 #14 Oct 21 2023 15:51:17
%S A366757 1,6,24,144,720,5040,42096,399000,3753960,47500992,479001600,
%T A366757 6230615736,87178291200,1457696910960,20929670124480,379536693283440,
%U A366757 6510917252872320,121831439598033840,2432921507427445440,53921727651043042560,1134312679767378217920
%N A366757 a(n) is the sum of the divisors of n!-1.
%F A366757 a(n) = sigma(n!-1) = A000203(A033312(n)).
%e A366757 a(5) = 144 because the divisors of 5!-1 are {1, 7, 17, 119}.
%p A366757 a:=n->numtheory[sigma](n!-1):
%p A366757 seq(a(n), n=2..30);
%t A366757 DivisorSigma[1,Range[2,25]!-1] (* _Paolo Xausa_, Oct 21 2023 *)
%o A366757 (Python)
%o A366757 from math import factorial
%o A366757 from sympy import divisor_sigma
%o A366757 def A366757(n): return divisor_sigma(factorial(n)-1) # _Chai Wah Wu_, Oct 20 2023
%Y A366757 Cf. A033312, A000203, A064145, A062569, A366758.
%K A366757 nonn
%O A366757 2,2
%A A366757 _Sean A. Irvine_, Oct 20 2023