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A119601
a(n) = 4*Product_{i=1..2n-1} (3^i+1)^2.
0
4, 64, 5017600, 2008645953126400, 5124408580006984170864640000, 85495432669493277396354169745064287272960000, 9355246290649672947599943358541996936410690283965618585600000000, 6716146186611919497047421474121060203152077041964192052138083160878210999543398400000000, 31633930525439354064905560668985964653660262913501499819669450560971550674840773249412865611450669691043840000000000
OFFSET
0,1
LINKS
R. Chapman et al., 2-modular lattices from ternary codes, J. Th. des Nombres de Bordeaux, 14 (2002), 73-85.
MATHEMATICA
Table[4*Product[(3^i+1)^2, {i, 2n-1}], {n, 0, 8}] (* James C. McMahon, Sep 17 2024 *)
PROG
(PARI) a(n) = 4*prod(i=1, 2*n-1, (3^i+1)^2); \\ Michel Marcus, Oct 28 2015
CROSSREFS
Sequence in context: A033635 A138835 A234608 * A058438 A171959 A041119
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 04 2006
STATUS
approved