cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A363247 a(0) = 0. a(n) = the smallest nonnegative integer, excluding a(n-1), not occurring in all occurrences of a(n-1)'s eight neighbors thus far in a square spiral.

Original entry on oeis.org

0, 1, 2, 3, 4, 1, 5, 2, 4, 5, 3, 6, 0, 7, 1, 8, 0, 9, 2, 8, 6, 4, 7, 8, 10, 0, 11, 1, 10, 2, 11, 4, 12, 2, 13, 3, 9, 5, 12, 3, 14, 0, 15, 1, 14, 5, 13, 4, 15, 2, 16, 1, 17, 0, 18, 1, 19, 0, 20, 1, 21, 0, 22, 1, 23, 0, 24, 1, 25, 0, 26, 1, 27, 0, 28, 2, 17, 3
Offset: 0

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Author

Gavin Lupo, May 24 2023

Keywords

Examples

			The spiral begins:
  0---8---1---7---0
  |               |
  9   4---3---2   6
  |   |       |   |
  2   1   0---1   3   .
  |   |           |   .
  8   5---2---4---5   .
  |                   |
  6---4---7---8---10--0
a(0) = 0
a(1) = 1. Smallest integer that's not a neighbor to every 0 = 1.
a(2) = 2. Smallest integer that's not a neighbor to every 1 = 2.
a(3) = 3. Smallest integer that's not a neighbor to every 2 = 3.
a(4) = 4. Smallest integer that's not a neighbor to every 3 = 4.
a(5) = 1. Smallest integer that's not a neighbor to every 4 = 1.
		

Crossrefs