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!)
A263794 Number of (n+1) X (3+1) 0..1 arrays with each row and column divisible by 3, read as a binary number with top and left being the most significant bits, and rows and columns lexicographically nonincreasing. 2
3, 3, 7, 7, 14, 14, 25, 25, 41, 41, 63, 63, 92, 92, 129, 129, 175, 175, 231, 231, 298, 298, 377, 377, 469, 469, 575, 575, 696, 696, 833, 833, 987, 987, 1159, 1159, 1350, 1350, 1561, 1561, 1793, 1793, 2047, 2047, 2324, 2324, 2625, 2625, 2951, 2951, 3303, 3303 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A263799.

LINKS

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

FORMULA

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

Empirical: a(n) = A058187(n-1) + floor((n+3)/2). - Filip Zaludek, Dec 14 2016

Conjectures from Colin Barker, Dec 14 2016: (Start)

a(n) = (n^3 + 6*n^2 + 32*n + 48)/48 for n even.

a(n) = (n^3 + 9*n^2 + 47*n + 87)/48 for n odd.

G.f.: x*(3 - 5*x^2 + 4*x^4 - x^6) / ((1 - x)^4*(1 + x)^3).

(End)

EXAMPLE

Some solutions for n = 5:

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

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

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

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

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

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

CROSSREFS

Cf. A058187, A263799.

Sequence in context: A325344 A208474 A187781 * A086530 A147402 A052551

Adjacent sequences:  A263791 A263792 A263793 * A263795 A263796 A263797

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 26 2015

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 May 30 14:31 EDT 2020. Contains 334724 sequences. (Running on oeis4.)