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 A033466 #16 Oct 15 2024 15:43:02
%S A033466 2,10,10,170,442,962,1850,650,5330,8282,12322,17690,986,33490,44522,
%T A033466 58082,74530,18850,117650,145162,177242,214370,51410,305810,361202,
%U A033466 423802,494210,114610,660970,758642
%N A033466 Denominators of the first differences of 1/(n^2 + 1).
%H A033466 G. C. Greubel, <a href="/A033466/b033466.txt">Table of n, a(n) for n = 0..2000</a>
%F A033466 For all n not in A016873, a(n) = n^4 + 2n^3 + 3n^2 + 2n + 2, else A099024((n-2)/5). - _Ralf Stephan_, Sep 25 2004
%F A033466 a(n) = denominator of (2*n+1)/((n^2+1)*((n+1)^2+1)). - _G. C. Greubel_, Oct 14 2024
%t A033466 Table[Denominator[(1+2*n)/((1+n^2)*(1+(n+1)^2))], {n,0,40}] (* _G. C. Greubel_, Oct 14 2024 *)
%o A033466 (Magma)
%o A033466 A033466:= func< n | Denominator((2*n+1)/((n^2+1)*((n+1)^2+1))) >;
%o A033466 [A033466(n): n in [0..40]]; // _G. C. Greubel_, Oct 14 2024
%o A033466 (SageMath)
%o A033466 def A033466(n): return denominator((2*n+1)/((n^2+1)*((n+1)^2+1)))
%o A033466 [A033466(n) for n in range(41)] # _G. C. Greubel_, Oct 14 2024
%Y A033466 Cf. A033465 (numerators).
%K A033466 nonn,frac
%O A033466 0,1
%A A033466 _N. J. A. Sloane_