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A300154 Consider a spiral on an infinite hexagonal grid. a(n) is the number of cells in the part of the spiral from 1st to n-th cell that are on the same column or diagonal (in any of three directions) as the n-th cell along the spiral, including that cell itself. 1
1, 2, 3, 3, 4, 4, 5, 5, 5, 6, 6, 7, 6, 7, 7, 8, 7, 8, 9, 8, 9, 8, 9, 10, 9, 10, 11, 9, 10, 11, 10, 11, 12, 10, 11, 12, 13, 11, 12, 13, 11, 12, 13, 14, 12, 13, 14, 15, 12, 13, 14, 15, 13, 14, 15, 16, 13, 14, 15, 16, 17, 14 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A138099 and A280026 are analogs for the square grid. - Andrey Zabolotskiy, Mar 05 2018

LINKS

Table of n, a(n) for n=1..62.

Emily Chitwood, Example of cell sight

Emily Chitwood, Example of spiral path

Emily Chitwood, Example of initial terms

EXAMPLE

a(3) = 3 because the third hexagon is on the same diagonal as itself, the second hexagon, and the original hexagon.

a(7) = 5 because the 7th cell is on the same columns/diagonals as cells No. 2 (in one direction), 6 (in another direction), 1 and 4 (in the third direction), plus itself.

CROSSREFS

Sequence in context: A000267 A249728 A060020 * A166127 A143502 A070984

Adjacent sequences:  A300151 A300152 A300153 * A300155 A300156 A300157

KEYWORD

nonn,easy

AUTHOR

Emily Chitwood and Kimberly Johnsen, Feb 26 2018

STATUS

approved

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Last modified December 11 19:37 EST 2018. Contains 318049 sequences. (Running on oeis4.)