A207695 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 1 1 vertically

9, 81, 144, 256, 768, 2304, 5856, 14884, 42700, 122500, 320600, 839056, 2361448, 6646084, 17633520, 46785600, 130315680, 362978704, 970889920, 2596921600, 7186175360, 19885512256, 53475523456, 143804774656, 396160887744

Offset

1,1

Comments

Row 4 of A207693

Links

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

Formula

Empirical: a(n) = 2*a(n-3) +64*a(n-4) +16*a(n-5) +4*a(n-6) -20*a(n-7) -1112*a(n-8) -324*a(n-9) +40*a(n-10) -136*a(n-11) +7516*a(n-12) +2032*a(n-13) -192*a(n-14) +1936*a(n-15) -23584*a(n-16) -4720*a(n-17) -5888*a(n-19) +37360*a(n-20) +3968*a(n-21) +480*a(n-22) +6464*a(n-23) -29872*a(n-24) -704*a(n-25) -256*a(n-26) -2592*a(n-27) +11072*a(n-28) -256*a(n-29) -64*a(n-30) +320*a(n-31) -1600*a(n-32) +64*a(n-33) +64*a(n-36) for n>39

Example

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

Crossrefs

Sequence in context: A209225 A208502 A175370 * A158028 A207591 A207924

Adjacent sequences: A207692 A207693 A207694 * A207696 A207697 A207698

Keyword

nonn

Author

R. H. Hardin Feb 19 2012

Status

approved