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A214665 The y-coordinates of prime numbers in an Ulam spiral oriented counterclockwise with first step east. 13
0, 1, 1, -1, 0, 2, 2, 0, -2, 1, 3, 3, -1, -3, -3, 0, 4, 4, 2, -2, -4, -4, -3, 3, 5, 5, 3, -1, -3, -5, 0, 4, 6, 6, 2, 0, -6, -6, -6, -3, 3, 5, 7, 7, 7, 5, -7, -7, -6, -4, 0, 6, 8, 8, 8, 2, -4, -6, -8, -8, -8, -5, 9, 9, 9, 9, 3, -3, -9, -9, -9, -9, -4, 2, 8, 10 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

The eight possible orientations of the Ulam spiral can be derived from combining either A214664 or A214666 with either A214665 or A214667 as ordered pairs of coordinates.

REFERENCES

See the March 1964 cover of Scientific American.

LINKS

William Rex Marshall, Table of n, a(n) for n = 1..10077 (coordinates of primes in a 325 X 325 square)

CROSSREFS

Cf. A000040, A063826, A214664, A214666, A214667.

Sequence in context: A114906 A259179 A214667 * A229723 A258040 A215879

Adjacent sequences:  A214662 A214663 A214664 * A214666 A214667 A214668

KEYWORD

sign,easy

AUTHOR

William Rex Marshall, Jul 26 2012

STATUS

approved

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Last modified May 12 21:06 EDT 2021. Contains 343829 sequences. (Running on oeis4.)