%I #43 Sep 18 2022 20:20:15
%S 1,3,33,4323,74748993,22349647743307203,
%T 1998027016999666984531472383425633,
%U 15968447842642350164774423714587589071259011612916483703599782377123
%N a(n) = A204321(n)/4.
%C Terms of the sequence can be presented as products of the following distinct prime factors: 1, 3, 3*11, 3*11*131, 3*11*131*17291, 3*11*131*17291*298995971. _Alexander R. Povolotsky_, Jan 19 2012
%C Those factors are A121897(m) for m >= 5. - _Alexander R. Povolotsky_, Jun 17 2012
%F a(n) = product(A126604(k), k=2...n) for n >= 2.
%Y Cf. A204321, A126604, A121897.
%K nonn
%O 1,2
%A _Alexander R. Povolotsky_, Jan 19 2012