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 A324480 Consider the numbers on the x-axis in the spiral shown in A274641; a(n) is the distance from n to the origin, or -1 if n never appears on the x-axis. 0
 0, 1, 1, 2, 2, 3, 4, 3, 7, 6, 4, 5, 8, 10, 5, 6, 7, 11, 8, 12, 14, 10, 18, 9, 9 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS It is conjectured that every nonnegative number appears on the x-axis exactly once. a(n) is also the distance to the origin from the point n+1 on the x-axis in A274640. Needs a large b-file: it will be interesting to see how irregular this sequence is. LINKS EXAMPLE The portion of the x-axis near 0 is: ... 14   6   5   4   2   0   1   3   7  10  11 ... and we see that both 1 and 2 are at distance 1 from 0. So a(1) = a(2) = 1. CROSSREFS Cf. A274640, A274641. The positive and negative x-axes are given in A274924 and A274928. Sequence in context: A284199 A284165 A284113 * A164975 A253889 A228754 Adjacent sequences:  A324477 A324478 A324479 * A324481 A324482 A324483 KEYWORD nonn,more AUTHOR N. J. A. Sloane, Mar 11 2019 STATUS approved

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Last modified August 22 20:47 EDT 2019. Contains 326209 sequences. (Running on oeis4.)