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A153940 Number of planar n X n X n binary triangular grids symmetric both under 120 degree rotation and reflection with no more than 5 ones in any 3 X 3 X 3 subtriangle. 0
1, 2, 2, 3, 7, 12, 23, 97, 172, 639, 2729, 9135, 35231, 283089, 990826, 7193827, 60573511, 397978987, 3029188158, 47855760575, 329376229908, 4705117486982, 77869569220480, 1005969603691107, 15055192931186105, 467694688000143716 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..25.

CROSSREFS

Sequence in context: A234850 A127165 A100683 * A049905 A167348 A068524

Adjacent sequences:  A153937 A153938 A153939 * A153941 A153942 A153943

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 03 2009

STATUS

approved

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Last modified May 16 14:39 EDT 2021. Contains 343949 sequences. (Running on oeis4.)