A206571 Number of nX2 0..3 arrays avoiding the pattern z-1 z-1 z in any row, column or nw-to-se diagonal

16, 256, 3721, 53824, 777924, 11242609, 162486009, 2348371600, 33940324441, 490529342884, 7089470711236, 102461949277801, 1480851163185241, 21402288176353681, 309320714104227225, 4470517516089946896

Offset

1,1

Comments

Column 2 of A206577

Links

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

Formula

Empirical: a(n) = 16*a(n-1) -12*a(n-2) -166*a(n-3) +134*a(n-4) +1595*a(n-5) -1291*a(n-6) -11538*a(n-7) +9401*a(n-8) +344*a(n-9) -2098*a(n-10) +2832*a(n-11) -1207*a(n-12) -846*a(n-13) +548*a(n-14) +637*a(n-15) -488*a(n-16) +102*a(n-17) -13*a(n-18) -161*a(n-19) +85*a(n-20) +20*a(n-21) -14*a(n-22) -4*a(n-23) +6*a(n-24) -4*a(n-25) +a(n-26) +2*a(n-27) -a(n-28)

Example

Some solutions for n=4
..2..2....1..3....1..0....2..0....0..0....0..2....3..1....2..3....3..3....1..0
..1..0....0..1....2..3....1..0....3..0....1..1....1..2....3..0....0..1....1..3
..0..3....0..0....2..1....2..0....1..2....3..1....0..1....1..2....0..0....1..3
..0..0....2..0....1..0....1..2....2..0....0..0....0..0....3..2....3..2....3..1

Crossrefs

Sequence in context: A294329 A267929 A122609 * A206791 A221665 A227592

Adjacent sequences: A206568 A206569 A206570 * A206572 A206573 A206574

Keyword

nonn

Author

R. H. Hardin Feb 09 2012

Status

approved