A204687 a(n) = A204321(n)/4.

1, 3, 33, 4323, 74748993, 22349647743307203, 1998027016999666984531472383425633, 15968447842642350164774423714587589071259011612916483703599782377123

Offset: 1

Author

Alexander R. Povolotsky, Jan 19 2012

Keywords

• nonn

Comments

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

Those factors are A121897(m) for m >= 5. - Alexander R. Povolotsky, Jun 17 2012

Crossrefs

Cf. A204321, A126604, A121897.

Formula

a(n) = product(A126604(k), k=2...n) for n >= 2.