A331348 - OEIS

A331348

Fill an infinite square array by following a spiral around the origin; if the square at position (x, y) is empty then set either T(x, y) = 1 or T(x, y) = T(2*x, 2*y) = 2 such that the RUNS transform of the sequence of values as they are chosen equals the sequence of values as they are visited; first choose the value 1. This sequence corresponds to the values as they are visited.

1, 2, 2, 1, 1, 2, 1, 2, 2, 1, 2, 2, 2, 2, 1, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 2, 1, 2, 2, 1, 1, 2, 2, 1, 2, 2, 1, 2, 2, 1, 1, 2, 2, 1, 2, 2, 1, 2, 1, 2, 1, 2, 2, 1, 2, 1, 1, 2, 2, 1

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OFFSET

0,2

COMMENTS

The sequence {a(n)} gives the values as they are visited, while, say {b(n)}, gives the values as they are chosen; so:

- a "2" will account for two terms in {a(n)} and for one term in {b(n)},

- a "1" will account for one term in both sequences,

- {a(n)} = RUNS({b(n)}).

LINKS

Table of n, a(n) for n=0..86.

Rémy Sigrist, PARI program for A331348

Rémy Sigrist, Scatterplot of (x, y) such that T(x, y)=1 and -500 <= x, y, <= 500