A230906 Number of nX4 0..3 arrays x(i,j) with each element horizontally, vertically or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, no adjacent elements equal, and upper left element zero

0, 26, 152, 802, 4308, 23614, 130178, 718750, 3970738, 21941252, 121252356, 670093980, 3703301746, 20466628218, 113111135842, 625122784014, 3454822416978, 19093535079990, 105522984179168, 583187006699888

Offset

1,2

Comments

Column 4 of A230910

Links

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

Formula

Empirical: a(n) = 20*a(n-1) -174*a(n-2) +877*a(n-3) -2835*a(n-4) +6037*a(n-5) -8100*a(n-6) +5354*a(n-7) +1632*a(n-8) -5940*a(n-9) +3068*a(n-10) +2069*a(n-11) -3724*a(n-12) +2559*a(n-13) +882*a(n-14) -5020*a(n-15) +2708*a(n-16) +3962*a(n-17) -3859*a(n-18) -890*a(n-19) +2032*a(n-20) -318*a(n-21) -643*a(n-22) +197*a(n-23) +81*a(n-24) -10*a(n-25) -35*a(n-26) +15*a(n-27) -a(n-28) for n>31

Example

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

Crossrefs

Sequence in context: A248465 A014552 A192289 * A232585 A042314 A280213

Adjacent sequences: A230903 A230904 A230905 * A230907 A230908 A230909

Keyword

nonn

Author

R. H. Hardin, Nov 01 2013

Status

approved