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A275606
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Spiral constructed on the nodes of the triangular net such that a(n) = signum(A274920(n)).
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7
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0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0
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OFFSET
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0
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COMMENTS
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The structure of the spiral has the following properties:
1) The 1's represent the nodes of the hexagonal net.
2) Every 0 is surrounded by six equidistant 1's.
3) Every 1 is surrounded by three equidistant 0's and three equidistant 1's.
4) Diagonals are periodic sequences with period 3 (A011655).
Also the 1's represent the atoms of carbon in graphene.
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LINKS
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FORMULA
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EXAMPLE
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Illustration of initial terms as a spiral:
.
. 1 - 0 - 1 - 1 - 0 - 1
. / \
. 0 1 - 1 - 0 - 1 - 1 0
. / / \ \
. 1 1 0 - 1 - 1 - 0 1 1
. / / / \ \ \
. 1 0 1 1 - 0 - 1 1 0 1
. / / / / \ \ \ \
. 0 1 1 0 1 - 1 0 1 1 0
. / / / / / \ \ \ \ \
. 1 1 0 1 1 0 - 1 1 0 1 1
. \ \ \ \ \ / / / /
. 0 1 1 0 1 - 1 - 0 1 1 0
. \ \ \ \ / / /
. 1 0 1 1 - 0 - 1 - 1 0 1
. \ \ \ / /
. 1 1 0 - 1 - 1 - 0 - 1 1
. \ \ /
. 0 1 - 1 - 0 - 1 - 1 - 0
. \
. 1 - 0 - 1 - 1 - 0 - 1
.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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