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A275610
Hexagonal spiral constructed on the nodes of the triangular net in which every 1 of A275606 is replaced with the least positive integer not yet in the sequence.
6
0, 1, 2, 3, 4, 5, 6, 0, 7, 0, 8, 0, 9, 0, 10, 0, 11, 0, 12, 13, 14, 0, 15, 16, 0, 17, 18, 0, 19, 20, 0, 21, 22, 0, 23, 24, 0, 25, 0, 26, 27, 28, 0, 29, 30, 31, 0, 32, 33, 34, 0, 35, 36, 37, 0, 38, 39, 40, 0, 41, 42, 0, 43, 44, 0, 45, 0, 46, 47, 0, 48, 0, 49, 50, 0, 51, 0, 52, 53, 0, 54, 0, 55, 56, 0, 57, 0, 58, 59, 0, 60
OFFSET
0,3
COMMENTS
A way for the enumeration of the nodes of the hexagonal net.
Also a way for the enumeration of the atoms of carbon in graphene.
Also sequence in which every positive integer of A274920 is replaced with the least positive integer not yet in the sequence.
EXAMPLE
Illustration of initial terms as a spiral:
.
. 9 - 0 - 8
. / \
. 0 3 - 2 0
. / / \ \
. 10 4 0 - 1 7
. \ \ /
. 0 5 - 6 - 0
. \
. 11 - 0 - 12
.
CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, Aug 03 2016
STATUS
approved