A068225 Neighbor in 1-2 direction of numbers arranged as clockwise spiral.

2, 11, 12, 3, 4, 1, 8, 9, 10, 27, 28, 29, 30, 13, 14, 15, 16, 5, 6, 7, 22, 23, 24, 25, 26, 51, 52, 53, 54, 55, 56, 31, 32, 33, 34, 35, 36, 17, 18, 19, 20, 21, 44, 45, 46, 47, 48, 49, 50, 83, 84, 85, 86, 87, 88, 89, 90, 57, 58, 59, 60, 61, 62, 63, 64, 37, 38, 39, 40, 41, 42, 43

Offset: 1

Author

Frank Ellermann, Feb 22 2002

Keywords

• nonn
• easy

Examples

			For example, if the spiral is oriented such that 1 is immediately to the right of 2, as shown below, then a(2) = 11 because 11 is immediately to the right of 2.
  21--22--23--24--25--26
  |                    |
  20  7---8---9---10  27
  |   |            |   |
  19  6   1---2   11  28
  |   |       |    |   |
  18  5---4---3   12  29
  |                |   |
  17--16--15--14--13  30
                       |
  36--35--34--33--32--31
		

Links

• Peter Kagey, Table of n, a(n) for n = 1..10000
• Frank Ellermann, Some EIS sequences based on a spiral of natural numbers.
• Index entries for sequences that are permutations of the natural numbers.

Crossrefs

Cf. A068226 (inverse, left), A334751 (above), A334752 (below).

Cf. A054552 (middle row right), A054567 (middle row left).