A262333 Number of (n+3) X (1+3) 0..1 arrays with each row and column divisible by 9, read as a binary number with top and left being the most significant bits.

2, 4, 8, 15, 29, 57, 114, 228, 456, 911, 1821, 3641, 7282, 14564, 29128, 58255, 116509, 233017, 466034, 932068, 1864136, 3728271, 7456541, 14913081, 29826162, 59652324, 119304648, 238609295, 477218589, 954437177, 1908874354, 3817748708

Offset

1,1

Links

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

Formula

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

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

Example

Some solutions for n=4:
..0..0..0..0....1..0..0..1....0..0..0..0....1..0..0..1....0..0..0..0
..0..0..0..0....1..0..0..1....1..0..0..1....1..0..0..1....1..0..0..1
..0..0..0..0....1..0..0..1....1..0..0..1....1..0..0..1....0..0..0..0
..0..0..0..0....0..0..0..0....1..0..0..1....1..0..0..1....0..0..0..0
..0..0..0..0....1..0..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..1....1..0..0..1....0..0..0..0
..0..0..0..0....1..0..0..1....1..0..0..1....0..0..0..0....0..0..0..0

Crossrefs

Column 1 of A262338.

Sequence in context: A275544 A000078 A176503 * A293335 A344687 A301480

Adjacent sequences: A262330 A262331 A262332 * A262334 A262335 A262336

Keyword

nonn

Author

R. H. Hardin, Sep 18 2015

Status

approved