A336350 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A336350

Square spiral of distinct nonnegative integers constructed by greedy algorithm, such that two terms on the same row or on the same column have no common one bit in their binary representations.

0, 1, 2, 4, 8, 6, 16, 3, 12, 32, 24, 64, 5, 48, 72, 128, 256, 17, 96, 512, 10, 33, 144, 320, 1024, 516, 192, 1280, 2048, 4096, 9, 130, 1536, 288, 2112, 4100, 8192, 514, 160, 6144, 16384, 32768, 13, 1152, 768, 10240, 20480, 65536, 18, 32800, 12288, 2304, 640

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

COMMENTS

We can always extend the sequence with a power of 2 greater than any previous term, so the sequence is well defined.

For symmetry reasons, we obtain the same sequence when considering a clockwise or a counterclockwise square spiral, or when initially moving towards any unit direction.

LINKS

Rémy Sigrist, Table of n, a(n) for n = 0..10200

Rémy Sigrist, Colored representation of the spiral for -250 <= x <= 250 and -250 <= y <= 250 (where the hue is function of a(n) and black pixels indicate powers of 2)

Rémy Sigrist, PARI program for A336350

EXAMPLE

The spiral begins:

264------80--262144---81920----5120---32896----2560----8224-------7

| |

49152 8192----4100----2112-----288----1536-----130-------9 65552

| | | |

3072 514 256-----128------72------48-------5 4096 131072

| | | | | |

4608 160 17 8-------4-------2 64 2048 17408

| | | | | | | |

73728 6144 96 6 0-------1 24 1280 640

| | | | | | |

393216 16384 512 16-------3------12------32 192 2304

| | | | |

524288 32768 10------33-----144-----320----1024-----516 12288

| | |

1048576 13----1152-----768---10240---20480---65536------18---32800

19---65792---18432----9216---33280--655360--266240-2097152-1048584

PROG

(PARI) See Links section.

CROSSREFS

See A336349 for a similar sequence.

Sequence in context: A269382 A253886 A253885 * A140692 A048640 A242353

Adjacent sequences: A336347 A336348 A336349 * A336351 A336352 A336353

KEYWORD

nonn,look,base

AUTHOR

Rémy Sigrist, Jul 19 2020

STATUS

approved