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A153989
Number of planar n X n X n binary triangular grids with every one adjacent to exactly 2 other ones.
0
1, 1, 2, 5, 11, 46, 267, 1767, 17587, 243760, 4437947, 112889388, 3947281130, 187476143214, 12242161648191, 1095392081180001, 134002137948473492, 22462563463091094957, 5156385913433257078626
OFFSET
0,3
CROSSREFS
Sequence in context: A128231 A088148 A088149 * A160859 A106887 A236044
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 04 2009
STATUS
approved