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 A046983 #16 Sep 05 2023 13:11:05
%S A046983 1,1,1,3,3,15,45,315,63,2835,14175,155925,93555,6081075,42567525,
%T A046983 638512875,127702575,10854718875,97692469875,1856156927625,
%U A046983 371231385525,194896477400625,2143861251406875,2900518163668125,2275791174570375
%N A046983 Denominators of Taylor series for tan(x + Pi/4).
%D A046983 G. W. Caunt, Infinitesimal Calculus, Oxford Univ. Press, 1914, p. 477.
%H A046983 T. D. Noe, <a href="/A046983/b046983.txt">Table of n, a(n) for n=0..100</a>
%e A046983 1 + 2*x + 2*x^2 + (8/3)*x^3 + (10/3)*x^4 + (64/15)*x^5 + (244/45)*x^6 + ...
%p A046983 A046983 := proc(n)
%p A046983 coeftayl(tan(x+Pi/4),x=0,n) ;
%p A046983 denom(%) ;
%p A046983 end proc: # _R. J. Mathar_, Jan 22 2017
%t A046983 nmax = 24; t[0, 1] = 1; t[0, _] = 0; t[n_, k_] := t[n, k] = (k-1)*t[n-1, k-1] + (k+1)*t[n-1, k+1]; Denominator[ Table[ Sum[ t[n, k]/n!, {k, 0, n+1}], {n, 0, nmax} ]] (* _Jean-François Alcover_, Nov 09 2011 *)
%t A046983 CoefficientList[Series[Tan[x+Pi/4],{x,0,30}],x]//Denominator (* _Harvey P. Dale_, Sep 05 2023 *)
%Y A046983 Cf. A046982.
%K A046983 nonn,frac,easy,nice
%O A046983 0,4
%A A046983 _N. J. A. Sloane_