login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A295270 Number of n X 3 0..1 arrays with each 1 horizontally or vertically adjacent to 0, 1 or 4 1s. 1
7, 33, 164, 811, 4035, 19997, 99245, 492401, 2443097, 12121712, 60143345, 298407987, 1480586061, 7346099129, 36448521869, 180843564461, 897276298340, 4451940313371, 22088817679653, 109596228179271, 543774384192739 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A295275.

LINKS

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

Robert Israel, Maple-assisted proof of formula

FORMULA

Empirical: a(n) = 2*a(n-1) + 10*a(n-2) + 20*a(n-3) + 17*a(n-4) - a(n-5) - 9*a(n-6) - 12*a(n-7) - a(n-8) - a(n-9) + a(n-10).

Empirical formula is true: see link. - Robert Israel, Nov 19 2017

EXAMPLE

Some solutions for n=7:

  0 1 0    1 0 0    0 0 0    1 0 0    0 1 0    0 1 1    0 0 0

  1 1 1    0 0 1    0 0 1    0 1 0    1 0 0    1 0 0    1 0 0

  0 1 0    0 0 0    0 0 0    1 0 0    0 0 1    1 0 0    0 0 1

  1 0 0    1 0 0    1 0 1    1 0 0    0 0 1    0 0 0    0 0 0

  0 0 1    0 1 0    0 0 0    0 0 0    1 1 0    1 0 0    0 1 0

  1 0 0    1 0 0    0 1 0    0 0 0    0 0 0    0 0 1    1 0 0

  0 1 1    0 1 1    0 0 0    0 0 0    1 0 1    1 0 0    0 0 0

CROSSREFS

Cf. A295275.

Sequence in context: A304278 A155603 A282991 * A275860 A054256 A085636

Adjacent sequences:  A295267 A295268 A295269 * A295271 A295272 A295273

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 19 2017

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 August 10 04:38 EDT 2020. Contains 336368 sequences. (Running on oeis4.)