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

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A207495 Number of n X 3 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 0 vertically. 2
6, 36, 102, 297, 932, 2974, 9723, 32164, 107568, 362291, 1226924, 4170948, 14218841, 48567776, 166128066, 568812225, 1948947544, 6681079858, 22911053867, 78586955264, 269607037796, 925049643523, 3174213970624, 10892652172048 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A207500.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 5*a(n-1) -2*a(n-2) -14*a(n-3) +6*a(n-4) +8*a(n-5) -a(n-6) -a(n-7) for n>8.

Empirical g.f.: x*(6 + 6*x - 66*x^2 - 57*x^3 + 119*x^4 + 72*x^5 - 19*x^6 - 11*x^7) / ((1 - x)*(1 - 2*x - x^2)*(1 - 2*x - 5*x^2 + x^4)). - Colin Barker, Mar 05 2018

EXAMPLE

Some solutions for n=4:

..0..0..1....0..1..0....1..1..0....1..1..1....1..0..0....0..1..0....1..0..1

..1..1..0....1..1..0....1..0..1....1..1..1....0..0..1....0..0..1....1..1..0

..0..0..1....1..1..0....1..1..0....0..1..0....1..0..0....0..1..0....0..0..1

..1..1..0....1..0..0....0..0..1....1..1..1....1..0..1....0..0..1....1..1..1

CROSSREFS

Cf. A207500.

Sequence in context: A207070 A207118 A207704 * A207249 A060521 A036141

Adjacent sequences:  A207492 A207493 A207494 * A207496 A207497 A207498

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 18 2012

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 December 10 20:23 EST 2019. Contains 329909 sequences. (Running on oeis4.)