login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A207438 Number of nX4 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 1 0 0 vertically 1
9, 81, 323, 1360, 6525, 32393, 165626, 855471, 4449491, 23211486, 121314285, 634633939, 3321850282, 17392770603, 91082814851, 477033173168, 2498544485965, 13087020633451, 68549369291830, 359063591740895, 1880798904630019 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A207442

LINKS

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

FORMULA

Empirical: a(n) = 8*a(n-1) +a(n-2) -120*a(n-3) +106*a(n-4) +730*a(n-5) -804*a(n-6) -2308*a(n-7) +2565*a(n-8) +4000*a(n-9) -4254*a(n-10) -3640*a(n-11) +3811*a(n-12) +1460*a(n-13) -1708*a(n-14) -82*a(n-15) +284*a(n-16) -48*a(n-17) for n>18

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Sequence in context: A207854 A207962 A207501 * A208138 A207444 A207428

Adjacent sequences:  A207435 A207436 A207437 * A207439 A207440 A207441

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 17 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 20 21:39 EDT 2022. Contains 353876 sequences. (Running on oeis4.)