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A153937 Number of planar n X n X n binary triangular grids symmetric both under 120 degree rotation and reflection with no more than 4 ones in any 5 X 5 X 5 subtriangle. 0
1, 2, 2, 3, 4, 4, 7, 20, 21, 45, 145, 212, 436, 2161, 2791, 8995, 40480, 86264, 264562, 1826697, 3632340, 16824438, 112933447, 337629371, 1472886340, 15531543956, 43332027600, 293975081405, 2889767925722, 12600532736321, 79696537663155 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..30.

CROSSREFS

Sequence in context: A036822 A056099 A084848 * A242971 A036818 A036813

Adjacent sequences:  A153934 A153935 A153936 * A153938 A153939 A153940

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 03 2009

STATUS

approved

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Last modified December 19 10:10 EST 2018. Contains 318246 sequences. (Running on oeis4.)