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A138234 Integers which land on a free spot on the plane, according to the compass method described below. 1
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 26, 28, 29, 30, 33, 34, 35, 36, 37, 39, 40, 44, 45, 46, 47, 48, 55, 56, 57, 58, 59, 60, 66, 67, 68, 69, 70, 77, 78, 79, 80, 88, 89, 90, 99, 100, 101, 102, 103, 104, 107, 108, 109, 111, 112 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Terms computed by Jean-Marc Falcoz.

LINKS

Table of n, a(n) for n=0..69.

Eric Angelini and Jean-Marc Falcoz Voyages de nombres.

Eric Angelini and Jean-Marc Falcoz, Voyages de nombres [Cached, with permission]

Eric Angelini and Jean-Marc Falcoz, Illustration

Eric Angelini and Jean-Marc Falcoz, Illustration [Cached, with permission]

EXAMPLE

..........................................

..................0.......................

...........9......*......1................

............*...........*.................

..........................................

.......8.*.................*.2............

..................X.......................

..........................................

.......7.*.................*.3............

..........................................

............*...........*.................

...........6......*......4................

..................5.......................

..........................................

Put an integer at the center of the compass (say, integer 5083) and move it by one step-unit successively in the direction given by its digit [in our example with 5083, we start at the center of the compass, then move one step-unit towards South (direction 5), then one step-unit towards North (direction 0), then one step-unit towards "8", then one step-unit towards "3": the integer 5083 would land precisely at the center of the compass]. Start to draw the landing point of each integer, one by one (see Illustration in the links for an animation); whenever an integer is about to land on an already occupied spot, the said integer is discarded from the sequence. [In our example, 5083 will be discarded because the center spot is occupied already by the number 16. So 16 is in the sequence but not 5083, nor 27, 38, 49, 50, etc.]

CROSSREFS

Sequence in context: A287478 A135579 A250251 * A324720 A247756 A032520

Adjacent sequences:  A138231 A138232 A138233 * A138235 A138236 A138237

KEYWORD

base,easy,nonn

AUTHOR

Jean-Marc Falcoz and Eric Angelini, May 05 2008

EXTENSIONS

Edited by Charles R Greathouse IV, Oct 28 2009

STATUS

approved

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Last modified November 21 01:23 EST 2019. Contains 329348 sequences. (Running on oeis4.)