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 A381845 #13 Mar 13 2025 08:56:32
%S A381845 1,1,8,48,192,3840,46080,322560,10321920,26542080,1857945600,
%T A381845 11678515200,1961990553600,25505877196800,1428329123020800,
%U A381845 42849873690624000,8903869857792000,46620662575398912000,2634762720116736000,31888533201572855808000,196237127394294497280000
%N A381845 a(n) = denominator( (e/Pi)*Integral_{x=-oo..+oo} cos(x)/(1 + x^2)^n dx ).
%e A381845 1, 1, 7/8, 37/48, 133/192, 2431/3840, 27007/46080, 176761/322560, ...
%t A381845 a[n_]:=Denominator[(E/Pi)Integrate[Cos[x]/(1 + x^2)^n,{x,-Infinity,Infinity}]]; Array[a,21]
%Y A381845 Cf. A061360, A061382, A143991 (conjectured numerators).
%K A381845 nonn,frac
%O A381845 1,3
%A A381845 _Stefano Spezia_, Mar 12 2025