A153920 - OEIS

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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

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OFFSET

0,2

LINKS

Table of n, a(n) for n=0..22.

CROSSREFS

Sequence in context: A220644 A338372 A376723 * A300483 A294241 A067579

Adjacent sequences: A153917 A153918 A153919 * A153921 A153922 A153923

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 03 2009

STATUS

approved