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 A170909 #9 Jun 24 2024 17:16:03
%S A170909 1,1,2,3,24,15,360,5040,40320,11340,1814400,39916800,47900160,
%T A170909 6227020800,7925299200,1307674368000,20922789888000,11115232128000,
%U A170909 3201186852864000,24329020081766400,48658040163532800,51090942171709440000,1124000727777607680000,5170403347776995328000
%N A170909 Denominators in Taylor series expansion of Product_{n >= 1} (1+x^n/n!).
%H A170909 H. Gingold, H. W. Gould, and M. E. Mays, <a href="https://www.researchgate.net/publication/268023169_Power_product_expansions">Power product expansions</a>, Util. Math., 34 (1988), 143-161.
%e A170909 1 + x + (1/2)*x^2 + (2/3)*x^3 + (5/24)*x^4 + (2/15)*x^5 + (41/360)*x^6 + (169/5040)*x^7 + ...
%t A170909 nmax=23; Denominator[CoefficientList[Series[Product[ (1+x^n/n!),{n,nmax}],{x,0,nmax}],x]] (* _Stefano Spezia_, Jun 24 2024 *)
%Y A170909 Cf. A170908.
%K A170909 nonn,frac
%O A170909 0,3
%A A170909 _N. J. A. Sloane_, Jan 30 2010
%E A170909 a(23) from _Stefano Spezia_, Jun 24 2024