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A153920
Number of planar n X n X n binary triangular grids symmetric under 120 degree rotation with no more than 3 ones in any 3 X 3 X 3 subtriangle.
0
1, 2, 2, 3, 10, 14, 49, 308, 775, 3862, 41331, 169669, 1449423, 25795923, 176879439, 2569800487, 77632066170, 900486220900, 21773916434861, 1104958273021411, 21496112349545252, 875306630139701071, 74586189583189934357
OFFSET
0,2
CROSSREFS
Sequence in context: A220644 A338372 A376723 * A300483 A294241 A067579
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 03 2009
STATUS
approved