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 A330030 #18 Mar 10 2020 23:46:59 %S A330030 1,1,2,3,6,30,30,42,210,42,210,2310,2310,30030,30030,30030,30030, %T A330030 39270,510510,1939938,9699690,9699690,9699690,17160990,223092870, %U A330030 903210,223092870,223092870,223092870,6469693230,6469693230,200560490130,200560490130,10555815270,200560490130 %N A330030 Least k such that Sum_{i=0..n} k^n / i! is a positive integer. %C A330030 Least k > 0 such that k^n/A061355(n) is an integer. %H A330030 Jinyuan Wang, <a href="/A330030/b330030.txt">Table of n, a(n) for n = 0..500</a> %F A330030 a(n) = A007947(A061355(n)). %e A330030 For n = 7, the denominator of Sum_{i=0..7} 1/i! is 252 = 2^2*3^2*7, so a(7) = 2*3*7 = 42. %o A330030 (PARI) a(n) = factorback(factorint(denominator(sum(i=2, n, 1/i!)))[, 1]); %Y A330030 Cf. A000142, A007947, A061354, A061355, A332734, A333196. %K A330030 nonn %O A330030 0,3 %A A330030 _Jinyuan Wang_, Mar 07 2020