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a(n) = A204321(n)/4.
0

%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