%I #6 Dec 30 2019 04:23:24
%S 1,6,105,5005,323323,30808063,3212440751,435656388001,63836474265323,
%T 12091972151626183,2500935283708076197,497341164867050876831,
%U 118511586608803381520987,31379946324498560236786747,8435082644934112984625042407,2416160765991941154223875519233,855269503485274999634523766244243
%N a(n) = Product_{k=n..2*n} prime(k).
%H Alexander Dirmeier, <a href="https://arxiv.org/abs/1912.11663">On Metrics Inducing the Fürstenberg Topology on the Integers</a>, arXiv:1912.11663 [math.GN], 2019. See p. 12.
%F a(n) = A002110(2*n)/A002110(n-1) for n>1.
%o (PARI) a(n) = prod(k=n, 2*n, prime(k));
%Y Cf. A000040 (primes), A002110 (primorials).
%K nonn
%O 0,2
%A _Michel Marcus_, Dec 30 2019