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A307011 First coordinate in a barycentric coordinate system of the points of a counterclockwise spiral on an hexagonal grid. Second and third coordinates are given in A307012 and A307013. 4
0, 1, 0, -1, -1, 0, 1, 2, 2, 1, 0, -1, -2, -2, -2, -1, 0, 1, 2, 3, 3, 3, 2, 1, 0, -1, -2, -3, -3, -3, -3, -2, -1, 0, 1, 2, 3, 4, 4, 4, 4, 3, 2, 1, 0, -1, -2, -3, -4, -4, -4, -4, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 5, 5, 5, 5, 4, 3, 2, 1, 0, -1, -2, -3, -4, -5 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,8

LINKS

Hugo Pfoertner, Table of n, a(n) for n = 0..10034

Hugo Pfoertner, Illustration of A307012 vs A307011, spiral.

Hugo Pfoertner, Illustration of A307013 vs A307011, spiral.

PROG

(PARI) r=-1; d=-1; print1(m=0, ", "); for(k=0, 8, for(j=1, r, print1(s, ", ")); if(k%2, , m++; r++); for(j=-m, m+1, if(d*j>=-m, print1(s=d*j, ", "))); d=-d)

CROSSREFS

Cf. A307012, A307013, A307014, A307016, A307017.

Numbers on the spokes of the spiral: A000567, A028896, A033428, A045944, A049450, A049451.

Sequence in context: A293680 A293539 A292469 * A285007 A194527 A104244

Adjacent sequences:  A307008 A307009 A307010 * A307012 A307013 A307014

KEYWORD

sign

AUTHOR

Hugo Pfoertner, Mar 19 2019

STATUS

approved

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Last modified October 15 07:38 EDT 2019. Contains 328026 sequences. (Running on oeis4.)