A181220 Number of n X 4 binary matrices with no three 1's adjacent in a line horizontally, vertically, diagonally or antidiagonally.

13, 169, 1209, 10732, 97764, 845531, 7426986, 65480503, 574725752, 5050028956, 44391722285, 390072820213, 3427866363455, 30124436697657, 264728435711181, 2326400950974628, 20444198985083330, 179661312288590309

Offset

1,1

Comments

Column 4 of A181224.

Links

R. H. Hardin, Table of n, a(n) for n=1..275

Formula

Empirical: a(n)=4*a(n-1)+27*a(n-2)+150*a(n-3)-59*a(n-4)-656*a(n-5)-2090*a(n-6)+4600*a(n-7)+558*a(n-8)-6222*a(n-9)+6935*a(n-10)-36512*a(n-11)+93343*a(n-12)-70961*a(n-13)+82681*a(n-14)-47047*a(n-15)-247244*a(n-16)+404537*a(n-17)-466677*a(n-18)+482071*a(n-19)-352513*a(n-20)+295888*a(n-21)-133016*a(n-22)+13672*a(n-23)-34436*a(n-24)+7664*a(n-25)+7816*a(n-26)+108*a(n-27)-620*a(n-28)-1024*a(n-29)+144*a(n-30)+32*a(n-31)+48*a(n-32).

Example

Some avoided solutions for 3 X 4
..0..1..0..1....1..0..0..0....0..0..1..0....1..0..0..0....0..0..0..1
..0..0..1..0....1..0..0..0....0..0..1..1....0..1..0..0....0..1..0..1
..0..1..0..0....1..1..0..0....0..0..1..0....1..0..1..0....0..0..0..1

Crossrefs

Cf. A181224.

Sequence in context: A221965 A206932 A206867 * A188562 A207084 A207178

Adjacent sequences: A181217 A181218 A181219 * A181221 A181222 A181223

Keyword

nonn

Author

R. H. Hardin Oct 10 2010

Status

approved