A222381 Sum of neighbor maps: number of n X 2 binary arrays indicating the locations of corresponding elements equal to the sum mod 3 of their horizontal and antidiagonal neighbors in a random 0..2 n X 2 array.

2, 16, 64, 232, 1024, 4096, 16224, 65536, 262144, 1047680, 4194304, 16777216, 67104256, 268435456, 1073741824, 4294944768, 17179869184, 68719476736, 274877800448, 1099511627776, 4398046511104, 17592185552896, 70368744177664

Offset

1,1

Comments

Column 2 of A222386.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) + 8*a(n-3) - 32*a(n-4) - 16*a(n-6) + 64*a(n-7).

Empirical g.f.: 2*x*(1 + 4*x - 20*x^3 + 16*x^4 + 32*x^6) / ((1 - 4*x)*(1 - 4*x^3)^2). - Colin Barker, Mar 15 2018

Example

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

Crossrefs

Cf. A222386.

Sequence in context: A212899 A127276 A076616 * A110048 A094505 A035598

Adjacent sequences: A222378 A222379 A222380 * A222382 A222383 A222384

Keyword

nonn

Author

R. H. Hardin, Feb 18 2013

Status

approved