A230836 Number of nX3 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, and upper left element zero

0, 22, 656, 16496, 416540, 10550264, 267165468, 6765343878, 171317073728, 4338219040702, 109855622302248, 2781846111459086, 70443984827525848, 1783835194151429142, 45171607024742624248, 1143869169017715821806

Offset

1,2

Comments

Column 3 of A230840

Links

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

Formula

Empirical: a(n) = 36*a(n-1) -321*a(n-2) +1424*a(n-3) -3860*a(n-4) +6696*a(n-5) +594*a(n-6) -70152*a(n-7) +320123*a(n-8) -856976*a(n-9) +1631595*a(n-10) -2066908*a(n-11) -1107106*a(n-12) +16080172*a(n-13) -51553020*a(n-14) +118926468*a(n-15) -245463204*a(n-16) +405589528*a(n-17) -400948880*a(n-18) +178336048*a(n-19) -94909520*a(n-20) +225948192*a(n-21) -117957824*a(n-22) -84255040*a(n-23) -5790912*a(n-24) -48408704*a(n-25) +37228544*a(n-26) -12355072*a(n-27) +4648960*a(n-28) -3346432*a(n-29) -225280*a(n-30) for n>31

Example

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

Crossrefs

Sequence in context: A369142 A218478 A223624 * A137262 A300137 A025760

Adjacent sequences: A230833 A230834 A230835 * A230837 A230838 A230839

Keyword

nonn

Author

R. H. Hardin, Oct 31 2013

Status

approved