A297521 Number of 3Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 or 3 neighboring 1s.

1, 11, 49, 128, 363, 1408, 5079, 16104, 52308, 180643, 616299, 2045926, 6825942, 23061538, 77737769, 260557844, 874178204, 2940510392, 9886875406, 33203436061, 111529068093, 374823089239, 1259590086969, 4231808883913, 14217990538402

Offset

1,2

Comments

Row 3 of A297519.

Links

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

Formula

Empirical: a(n) = a(n-1) +a(n-2) +10*a(n-3) +37*a(n-4) +23*a(n-5) +21*a(n-6) -25*a(n-7) -40*a(n-8) -44*a(n-9) +17*a(n-11) +5*a(n-12)

Example

Some solutions for n=7
..0..0..0..0..0..0..1. .0..0..0..0..0..0..0. .0..0..0..0..0..1..1
..0..1..0..0..0..1..0. .1..1..0..0..0..1..0. .0..0..0..0..0..0..0
..0..1..1..1..0..0..0. .1..0..1..0..1..0..0. .0..0..0..0..1..1..0

Crossrefs

Cf. A297519.

Sequence in context: A101992 A356792 A160671 * A295420 A003063 A124857

Adjacent sequences: A297518 A297519 A297520 * A297522 A297523 A297524

Keyword

nonn

Author

R. H. Hardin, Dec 31 2017

Status

approved