# Hexagonal Fibonacci

Neil Fernandez primeness at borve.demon.co.uk
Fri Jun 18 10:50:55 CEST 2004

```In message <017001c454f3\$790e8f80\$93b9763d at computer>, y.kohmoto

>    Hello, seqfans.
>    I considerd the same kind of generalized Fibonacci as A094767

<snip>

> %I  A000001
> %S A000001 1, 1, 2, 4, 7, 12, 20, 34, 55, 90, 148, 240, 394, 638
> %N A000001 A hexagonal spiral Fibonacci sequence
<snip>
> %C A000001                     12    20   34
> %C A000001                  7     1     1     55
> %C A000001               638   4     2     90
> %C A000001                 394    240  148
<snip>
> %I  A000002
> %S  A000002 0, 1, 1, 2, 3, 5, 8, 14, 23, 38, 63, 102,168, 272
> %N  A000002  A hexagonal spiral Fibonacci sequence
<snip>
> %C  A000002                    5    8    14
> %C  A000002                  3    0    1    23
> %C  A000002               272   2    1   38
> %C A000002                   168  102  63

Hi Yasutoshi,

did you also see:

%N A078510 Spiro-Fibonacci numbers, a(n) = sum of two previous terms
that are nearest when terms arranged in a spiral.

%N A079421 Spiro-Fibonacci differences, a(n) = difference of two
previous terms that are nearest when terms arranged in a spiral.

%N A079422 a(n) = number of 1's in the first n^2 Spiro-Fibonacci
differences.

<http://www.borve.demon.co.uk/primeness/spirofib.html>

where the link with cellular automata is clear.

Best regards,

Neil

--
Neil Fernandez

```