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 A228449 #14 Jul 04 2025 11:43:13
%S A228449 1,0,0,0,0,0,0,0,0,1,3,9,28,92,324,1217,4871,20703,93166,442542,
%T A228449 2212711,11616735,63892044,367379253,2204275523,13776722023,
%U A228449 89548693155,604453678799,4231175751597,30676024199079,230070181493096,1783043906571497,14264351252571976
%N A228449 a(n) = floor(n! / 4^n).
%t A228449 Table[Floor[n!/4^n],{n,0,40}] (* _Harvey P. Dale_, Jun 07 2014 *)
%o A228449 (Python)
%o A228449 import math
%o A228449 for n in range(99): print(math.factorial(n)//(4**n), end=', ')
%Y A228449 Cf. A000142, A066979, A212310.
%K A228449 nonn,less
%O A228449 0,11
%A A228449 _Alex Ratushnyak_, Oct 27 2013