A204860 Number of (n+2) X 3 0..1 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly two different ways, and new values 0..1 introduced in row major order

102, 382, 1437, 5352, 20113, 75595, 283877, 1066520, 4007148, 15055157, 56564804, 212519195, 798454799, 2999883555, 11270857666, 42345767978, 159097399097, 597745236156, 2245790151901, 8437664012699, 31701168874413, 119104542808892

Offset

1,1

Comments

Column 1 of A204867.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +7*a(n-2) -8*a(n-4) +22*a(n-6) +41*a(n-7) +22*a(n-8) +13*a(n-9) -270*a(n-10) +64*a(n-11) +392*a(n-12) -424*a(n-13) +24*a(n-14) -228*a(n-15) +304*a(n-16) +200*a(n-17) -192*a(n-18) +32*a(n-19).

Example

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

Crossrefs

Sequence in context: A140062 A203407 A204867 * A277459 A127655 A206659

Adjacent sequences: A204857 A204858 A204859 * A204861 A204862 A204863

Keyword

nonn

Author

R. H. Hardin, Jan 20 2012

Status

approved