OFFSET
0,1
LINKS
R. Chapman et al., 2-modular lattices from ternary codes, J. Th. des Nombres de Bordeaux, 14 (2002), 73-85.
FORMULA
a(n) = 4*A290000(n)^2. - Vaclav Kotesovec, Sep 17 2024
MATHEMATICA
Table[4*Product[(3^i+1)^2, {i, n-1}], {n, 0, 12}] (* James C. McMahon, Sep 17 2024 *)
PROG
(PARI) a(n) = 4*prod(i=1, n-1, (3^i+1)^2); \\ Michel Marcus, Oct 28 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 04 2006
STATUS
approved