A220172 Sum of neighbor maps: number of n X 1 binary arrays indicating the locations of corresponding elements equal to the sum mod 3 of their horizontal, vertical and antidiagonal neighbors in a random 0..2 n X 1 array.

2, 2, 8, 16, 24, 64, 128, 232, 512, 1024, 1984, 4096, 8192, 16224, 32768, 65536, 130688, 262144, 524288, 1047680, 2097152, 4194304, 8386560, 16777216, 33554432, 67104256, 134217728, 268435456, 536860672, 1073741824, 2147483648, 4294944768

Offset

1,1

Comments

Column 1 of A220177.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +4*a(n-3) -8*a(n-4) -4*a(n-6) +8*a(n-7).

Empirical g.f.: 2*(1 - x + 2*x^2 - 4*x^3 + 4*x^6) / ((1 - 2*x)*(1 - 2*x^3)^2). - Colin Barker, Feb 18 2018

Example

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

Crossrefs

Sequence in context: A098273 A342835 A361294 * A276054 A192305 A228797

Adjacent sequences: A220169 A220170 A220171 * A220173 A220174 A220175

Keyword

nonn

Author

R. H. Hardin, Dec 06 2012

Status

approved