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 A248684 #13 Feb 27 2023 08:04:28
%S A248684 2,7,1,8,7,0,2,6,4,1,9,1,0,8,5,1,4,9,7,0,8,6,7,5,2,2,0,0,2,8,7,7,5,6,
%T A248684 6,2,1,8,3,3,6,8,3,4,7,2,3,1,0,3,5,9,5,2,9,5,3,3,5,0,8,1,7,4,0,3,4,9,
%U A248684 4,7,0,0,8,4,4,5,0,8,3,5,1,0,9,9,5,8
%N A248684 Decimal expansion of r = sum{(floor(n/4)!)^4/n!, n >= 0}.
%H A248684 Clark Kimberling, <a href="/A248684/b248684.txt">Table of n, a(n) for n = 1..1000</a>
%F A248684 r = sum{(n!^4)*p(4,n)/(4*n + 3)!, n >= 0}, where p(k,n) is defined at A248664.
%e A248684 r = 2.718702641910851497086752200287756621...
%t A248684 RealDigits[Sum[(Floor[n/4])!^4/n!, {n, 0, 400}], 10, 111][[1]]
%o A248684 (PARI) suminf(n=0, ((n\4)!)^4/n!) \\ _Michel Marcus_, Feb 23 2016
%Y A248684 Cf. A248682, A248683, A248685, A248664.
%K A248684 nonn,easy,cons
%O A248684 1,1
%A A248684 _Clark Kimberling_, Oct 11 2014