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A153921 Number of planar n X n X n binary triangular grids with mirror symmetry about one altitude with no more than 3 ones in any 3 X 3 X 3 subtriangle. 0
1, 2, 4, 10, 28, 148, 714, 6039, 49623, 697824, 9570390, 228608398, 5268376882, 211052632687, 8181458661819, 550685739585810, 35868897568521948, 4059582510922093828, 444431993377350866570, 84536428851931450778591 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..19.

CROSSREFS

Sequence in context: A006841 A003223 A061417 * A189582 A060315 A148111

Adjacent sequences:  A153918 A153919 A153920 * A153922 A153923 A153924

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 03 2009

STATUS

approved

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Last modified January 19 20:41 EST 2020. Contains 331066 sequences. (Running on oeis4.)