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 A248683 #13 Feb 27 2023 08:04:14
%S A248683 2,7,3,0,2,5,6,3,7,6,9,6,3,3,6,1,3,8,5,8,0,4,9,8,3,2,7,4,4,7,7,1,9,7,
%T A248683 6,2,7,1,9,7,1,2,4,1,6,3,0,1,5,9,6,2,6,9,3,2,7,0,5,2,5,1,6,3,7,6,0,2,
%U A248683 6,1,9,7,5,9,1,8,6,8,3,7,1,4,6,1,7,4
%N A248683 Decimal expansion of r = sum{(floor(n/3)!)^3/n!, n >= 0}.
%H A248683 Clark Kimberling, <a href="/A248683/b248683.txt">Table of n, a(n) for n = 1..1000</a>
%F A248683 r = sum{(n!^3)*p(3,n)/(3*n + 2)!, n >= 0}, where p(k,n) is defined at A248664.
%e A248683 r = 2.7302563769633613858049832744771976271...
%t A248683 RealDigits[Sum[(Floor[n/3])!^3/n!, {n, 0, 400}], 10, 111][[1]]
%o A248683 (PARI) suminf(n=0, ((n\3)!)^3/n!) \\ _Michel Marcus_, Feb 23 2016
%Y A248683 Cf. A248682, A248684, A248685, A248664.
%K A248683 nonn,easy,cons
%O A248683 1,1
%A A248683 _Clark Kimberling_, Oct 11 2014