This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A195209 #13 Aug 02 2024 03:16:31
%S A195209 0,0,0,2,0,72,0,2704,0,268128,0,17621496,0,4974281208,0,549790303712,
%T A195209 0,245357774621280,0,67684833350266496,0,36434223374991414336,0,
%U A195209 10781900341537812480000,0,14585451990785851336761600,0,4706112122106541811177554944,0,5607912482098966721098538956800,0
%N A195209 Sum of even divisors of !n.
%H A195209 Amiram Eldar, <a href="/A195209/b195209.txt">Table of n, a(n) for n = 0..82</a>
%F A195209 From _Amiram Eldar_, Aug 02 2024: (Start)
%F A195209 a(n) = A146076(A000166(n)), for n != 1.
%F A195209 a(2*n) = 0. (End)
%e A195209 a(7) = 2704 because the divisors of !7 = 1854 are {1, 2, 3, 6, 9, 18, 103, 206, 309, 618, 927, 1854}, and the sum of the 6 even divisors 2, 6, 18, 206, 618 and 1854 is 2704.
%t A195209 Table[Total[Select[Divisors[Subfactorial[n]], EvenQ[ # ]&]], {n, 0, 25}]
%Y A195209 Cf. A000166, A146076, A195207, A195208, A195210.
%K A195209 nonn
%O A195209 0,4
%A A195209 _Michel Lagneau_, Sep 13 2011
%E A195209 a(26)-a(30) from _Amiram Eldar_, Aug 02 2024