A204392 Number of (n+2) X 4 0..1 arrays with no 3 X 3 subblock having three equal diagonal elements or three equal antidiagonal elements, and new values 0..1 introduced in row major order.

648, 4050, 27378, 175232, 1131008, 7311488, 47258642, 305390898, 1973176200, 12751406208, 82400136968, 532464529058, 3440804225762, 22234526147072, 143679727411200, 928460232000000, 5999721595740450, 38770275955862882

Offset

1,1

Comments

Column 2 of A204398.

Links

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

Formula

Empirical: a(n) = a(n-1) +15*a(n-2) +89*a(n-3) +211*a(n-4) +375*a(n-5) +149*a(n-6) -29*a(n-7) -195*a(n-8) -61*a(n-9) +61*a(n-10) +195*a(n-11) +29*a(n-12) -149*a(n-13) -375*a(n-14) -211*a(n-15) -89*a(n-16) -15*a(n-17) -a(n-18) +a(n-19).

Example

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

Crossrefs

Cf. A204398.

Sequence in context: A171606 A006914 A337313 * A233677 A200938 A165611

Adjacent sequences: A204389 A204390 A204391 * A204393 A204394 A204395

Keyword

nonn

Author

R. H. Hardin, Jan 15 2012

Status

approved