login
This site is supported by donations to The OEIS Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A187223 Differences between A147562 (Ulam-Warburton cellular automaton) and A187220 (Gullwing sequence). 1
0, 0, 2, 2, 6, 2, 6, 2, 14, 2, 6, 2, 14, 2, 6, -14, 30, 2, 6, 2, 14, 2, 6, -14, 30, 2, 6, -14, 22, -22, -34, -102, 62, 2, 6, 2, 14, 2, 6, -14, 30, 2, 6, -14, 22, -22, -34, -102, 62, 2, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Apparently the Gullwing sequence A187220 is the connection between the Ulam-Warburton C. A. (A147562) and the toothpick sequence A139250.

Note that the more complex structure is A187220, followed by A139250 and then A147562.

For another version which contains only positive terms and is more synchronous see the triangle A187564.

LINKS

Table of n, a(n) for n=0..50.

David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), 157-191. [There is a typo in Theorem 6: (13) should read u(n) = 4.3^(wt(n-1)-1) for n >= 2.]

N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS

FORMULA

a(n) = A147562(n) - A187220(n).

EXAMPLE

Contribution from Omar E. Pol, Aug 25 2012 (Start):

Written as a triangle the sequence begins:

0,

0,

2,

2,6,

2,6,2,14,

2,6,2,14,2,6,-14,30,

2,6,2,14,2,6,-14,30,2,6,-14,22,-22,-34,-102,62,

2,6,2,14,2,6,-14,30,2,6,-14,22,-22,-34,-102,62,2,6,...

(End)

CROSSREFS

Cf. A139250, A147562, A187220, A187564.

Sequence in context: A247451 A167268 A278162 * A175194 A086568 A239074

Adjacent sequences:  A187220 A187221 A187222 * A187224 A187225 A187226

KEYWORD

sign,tabf

AUTHOR

Omar E. Pol, Mar 11 2011

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 18 11:14 EST 2019. Contains 319271 sequences. (Running on oeis4.)