A153997 - OEIS

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A153997

Number of planar n X n X n binary triangular grids symmetric under 120 degree rotation with no more than 12 ones in any 5 X 5 X 5 subtriangle.

0

1, 2, 2, 4, 16, 31, 122, 973, 3890, 30317, 486144, 3845485, 61098761, 1952652536, 30753790733, 973261651722, 61980407029298, 1943138871957133, 122570367648067555

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Table of n, a(n) for n=0..18.

CROSSREFS

Sequence in context: A153991 A153994 A102864 * A154000 A154003 A291338

Adjacent sequences: A153994 A153995 A153996 * A153998 A153999 A154000

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 04 2009

STATUS

approved