This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A272573 Start a spiral of numbers on a hexagonal tiling, with the initial hexagon as a(1) = 1. a(n) is the smallest positive integer not equal to or previously adjacent to its neighbors. 2
 1, 2, 3, 4, 5, 6, 7, 4, 6, 8, 5, 9, 8, 10, 2, 11, 3, 10, 11, 12, 13, 9, 12, 7, 13, 14, 1, 11, 13, 15, 9, 16, 14, 7, 16, 17, 15, 1, 16, 18, 7, 17, 19, 20, 1, 17, 18, 19, 9, 21, 3, 20, 10, 22, 4, 15, 21, 23, 5, 22, 23, 10, 21, 6, 22, 24, 25, 2, 14, 22, 25, 26, 3 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This is the hexagonal analog to A260643. LINKS Peter Kagey, Table of n, a(n) for n = 1..10000 Peter Kagey, Ruby program for computing sequence. EXAMPLE Illustration of a(1) through a(8) and a(13):     |     |     |      |       |       |       |        |     | 8 9 5     |     |  3  | 4 3  |  4 3  |  4 3  |  4 3  |  4 3   |     |  4 3 8   1 | 1 2 | 1 2 |  1 2 | 5 1 2 | 5 1 2 | 5 1 2 | 5 1 2  | ... | 5 1 2 6     |     |     |      |       |  6    |  6 7  |  6 7 4 |     |  6 7 4 CROSSREFS Cf. A047932, A260643. Sequence in context: A115871 A138221 A038388 * A319999 A083501 A007922 Adjacent sequences:  A272570 A272571 A272572 * A272574 A272575 A272576 KEYWORD nonn AUTHOR Peter Kagey, May 03 2016 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified March 23 05:36 EDT 2019. Contains 321422 sequences. (Running on oeis4.)