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 A284994 #11 Jul 27 2024 03:53:05
%S A284994 1,1,0,1,1,2,3,6,11,24,52,120,287,720,1871,5040,14034,40320,119292,
%T A284994 362880,1133278,3628800,11899423,39916800,136843365,479001600,
%U A284994 1710542068,6227020800,23092317922,87178291200,334838609873,1307674368000,5189998453040
%N A284994 Floor(Gamma(n/2)).
%C A284994 The bisections are A000142 (factorials) and A014510.
%H A284994 Clark Kimberling, <a href="/A284994/b284994.txt">Table of n, a(n) for n = 1..500</a>
%F A284994 a(n) = floor(Gamma(n/2)).
%e A284994 Let s = sqrt(Pi); for n>=1, gamma(n/2) takes the values s, 1, s/2, 1, 3s/4, 2, 15s/8, 6, so that a(n) begins with 1,1,0,1,1,2,3,6.
%t A284994 Table[Floor[Gamma[n/2]], {n, 1, 35}]
%Y A284994 Cf. A000142, A014510, A284995.
%K A284994 nonn,easy
%O A284994 1,6
%A A284994 _Clark Kimberling_, Apr 08 2017