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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 April 23 13:56 EDT 2021. Contains 343204 sequences. (Running on oeis4.)