%I #14 May 30 2019 16:59:20
%S 1,2,2,6,10,210,22,30030,1870,149226,3910,6469693230,11594,
%T 7420738134810,3215630,741422598,2569288370,32589158477190044730,
%U 28045886,117288381359406970983270,19644868330,4812825965463978,23916676633630,3217644767340672907899084554130
%N a(n) = Product_{k=1..n, gcd(n,k) = 1} prime(k).
%F A001221(a(n)) = A000010(n).
%F a(A000040(n)) = A002110(A006093(n)).
%t a[n_] := Product[If[GCD[n, k] == 1, Prime[k], 1], {k, 1, n}]; Table[a[n], {n, 0, 23}]
%Y Cf. A000010, A000040, A001221, A001783, A002110, A005117, A006093, A127413.
%K nonn
%O 0,2
%A _Ilya Gutkovskiy_, May 30 2019