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A214664 The x-coordinates of prime numbers in an Ulam spiral oriented counterclockwise with first step east. 11
1, 1, -1, -1, 2, 2, -2, -2, 0, 3, 3, -3, -3, -3, 1, 4, 2, 0, -4, -4, -4, 2, 5, 5, -1, -5, -5, -5, -5, -3, 6, 6, 2, 0, -6, -6, -6, 0, 4, 7, 7, 7, -1, -3, -7, -7, -7, 5, 8, 8, 8, 8, 8, -2, -8, -8, -8, -8, -4, 0, 2, 9, 9, 5, 3, -1, -9, -9, -5, -3, 1, 7, 10, 10 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

COMMENTS

The eight possible orientations of the Ulam spiral can be derived by 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, A214665, A214666, A214667.

Sequence in context: A341894 A171932 A305629 * A214666 A320471 A333180

Adjacent sequences:  A214661 A214662 A214663 * A214665 A214666 A214667

KEYWORD

sign,easy

AUTHOR

William Rex Marshall, Jul 26 2012

STATUS

approved

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Last modified April 23 01:23 EDT 2021. Contains 343198 sequences. (Running on oeis4.)