A221664 Sum of neighbor maps: number of n X 3 binary arrays indicating the locations of corresponding elements equal to the sum mod 3 of their horizontal, diagonal and antidiagonal neighbors in a random 0..2 n X 3 array.

8, 64, 512, 3772, 32768, 262144, 2097152, 16777216, 134140928, 1073741824, 8589934592, 68719476736, 549755813888, 4398033385216, 35184372088832, 281474976710656, 2251799813685248, 18014398509481984, 144115185909972992

Offset

1,1

Comments

Column 3 of A221666.

Links

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

Formula

Empirical: a(n) = 8*a(n-1) +360*a(n-5) -2880*a(n-6) -47232*a(n-10) +377856*a(n-11) +2872320*a(n-15) -22978560*a(n-16) -92491776*a(n-20) +739934208*a(n-21) +1689550848*a(n-25) -13516406784*a(n-26) -18150850560*a(n-30) +145206804480*a(n-31) +113850187776*a(n-35) -910801502208*a(n-36) -386547056640*a(n-40) +3092376453120*a(n-41) +549755813888*a(n-45) -4398046511104*a(n-46).

Example

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

Crossrefs

Cf. A221666.

Sequence in context: A189155 A189337 A262335 * A228981 A222388 A222937

Adjacent sequences: A221661 A221662 A221663 * A221665 A221666 A221667

Keyword

nonn

Author

R. H. Hardin, Jan 21 2013

Status

approved