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 A046826 #17 Feb 21 2022 01:16:53
%S A046826 1,1,2,3,3,5,60,105,35,63,630,1155,6930,12870,24024,9009,9009,17017,
%T A046826 306306,2909907,692835,1322685,58198140,111546435,66927861,128707425,
%U A046826 371821450,717084225,20078358300,38818159380,2329089562800,4512611027925
%N A046826 Denominator of Sum_{k=0..n} 1/binomial(n,k).
%D A046826 See A046825, which is the main entry.
%H A046826 T. D. Noe, <a href="/A046826/b046826.txt">Table of n, a(n) for n=0..200</a>
%F A046826 a(n) = denominator( A003149(n)/n! ). - _G. C. Greubel_, May 24 2021
%e A046826 1, 2, 5/2, 8/3, 8/3, 13/5, 151/60, 256/105, 83/35, 146/63, 1433/630, 2588/1155, 15341/6930, 28211/12870, 52235/24024, 19456/9009, 19345/9009, ... = A046825/A046826
%t A046826 Denominator[Table[Sum[1/Binomial[n,k],{k,0,n}],{n,0,40}]] (* _Harvey P. Dale_, Nov 05 2011 *)
%o A046826 (Magma) [Denominator((&+[1/Binomial(n,j): j in [0..n]])): n in [0..40]]; // _G. C. Greubel_, May 24 2021
%o A046826 (Sage) [denominator(sum(1/binomial(n,j) for j in (0..n))) for n in (0..40)] # _G. C. Greubel_, May 24 2021
%Y A046826 Cf. A003149, A046825.
%K A046826 nonn,easy,frac,nice
%O A046826 0,3
%A A046826 _N. J. A. Sloane_