A220381 Majority value maps: number of n X 3 binary arrays indicating the locations of corresponding elements equal to at least half of their horizontal and antidiagonal neighbors in a random 0..1 n X 3 array.

4, 25, 136, 753, 4160, 22989, 127037, 702009, 3879313, 21437148, 118462034, 654623158, 3617458391, 19990134860, 110465815644, 610435923087, 3373279000591, 18640795512630, 103009344107857, 569231338133692

Offset

1,1

Comments

Column 3 of A220386.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) + 8*a(n-2) + 3*a(n-3) - 3*a(n-4) - 2*a(n-5).

Empirical g.f.: x*(4 + 9*x + 4*x^2 - 3*x^3 - 3*x^4) / (1 - 4*x - 8*x^2 - 3*x^3 + 3*x^4 + 2*x^5). - Colin Barker, Jul 31 2018

Example

Some solutions for n=3:
..0..0..1....0..0..1....0..0..1....1..1..1....0..0..1....1..1..1....1..1..0
..0..1..0....0..1..1....1..1..0....1..1..1....0..1..1....1..0..0....1..0..0
..1..0..0....1..1..0....0..0..1....1..0..0....0..1..1....0..0..1....0..0..0

Crossrefs

Cf. A220386.

Sequence in context: A304842 A156701 A273120 * A015533 A207410 A278275

Adjacent sequences: A220378 A220379 A220380 * A220382 A220383 A220384

Keyword

nonn

Author

R. H. Hardin, Dec 13 2012

Status

approved