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 A242569 #8 Oct 22 2024 16:04:10
%S A242569 -1,-2,0,16,110,708,5026,40304,362862,3628780,39916778,479001576,
%T A242569 6227020774,87178291172,1307674367970,20922789887968,355687428095966,
%U A242569 6402373705727964,121645100408831962,2432902008176639960,51090942171709439958,1124000727777607679956,25852016738884976639954,620448401733239439359952
%N A242569 n!-2n.
%C A242569 For n > 2, a(n) is the largest value of k such that (n!+k)/(n+k) is an integer.
%C A242569 For n > 2, a(n) is the largest value of k such that (n!+k)/(n+k) is prime.
%C A242569 For n > 1, a(n) is even.
%F A242569 a(n) = n!-2n.
%e A242569 3!-2*3 = 0 so a(3) = 0.
%e A242569 4!-2*4 = 16 so a(4) = 16.
%e A242569 5!-2*5 = 110 so a(5) = 110.
%t A242569 Table[n!-2n,{n,30}] (* _Harvey P. Dale_, Oct 22 2024 *)
%o A242569 (Python)
%o A242569 import math
%o A242569 {print(math.factorial(n)-2*n) for n in range(1,25)}
%o A242569 (PARI) for(n=1,25,print(n!-2*n))
%Y A242569 Cf. A000142, A242567, A242568.
%K A242569 sign
%O A242569 1,2
%A A242569 _Derek Orr_, May 17 2014