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