A204611 Number of (n+1)X4 0..1 arrays with the determinants of 2X2 subblocks nondecreasing rightwards and downwards

125, 749, 4901, 31805, 205117, 1322417, 8522985, 54938417, 354134921, 2282874145, 14716407353, 94869591953, 611581623337, 3942604144385, 25416311360025, 163848400648049, 1056262956080393, 6809292269424865, 43896707048892665

Offset

1,1

Comments

Column 3 of A204616

Links

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

Formula

Empirical: a(n) = 9*a(n-1) -8*a(n-2) -72*a(n-3) +96*a(n-4) +128*a(n-5) -128*a(n-6) -64*a(n-7) for n>10

Example

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

Crossrefs

Sequence in context: A253345 A016815 A253352 * A296037 A355885 A088896

Adjacent sequences: A204608 A204609 A204610 * A204612 A204613 A204614

Keyword

nonn

Author

R. H. Hardin Jan 17 2012

Status

approved