|
|
A197053
|
|
Number of nX7 0..4 arrays with each element equal to the number its horizontal and vertical zero neighbors
|
|
2
|
|
|
7, 26, 156, 692, 3580, 17742, 88056, 439338, 2192602, 10912392, 54394628, 271160024, 1351103246, 6733077562, 33557756016, 167232569172, 833404135538, 4153405692526, 20698773896328, 103153449929238, 514074952403758
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Every 0 is next to 0 0's, every 1 is next to 1 0's, every 2 is next to 2 0's, every 3 is next to 3 0's, every 4 is next to 4 0's
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 2*a(n-1) +9*a(n-2) +37*a(n-3) -187*a(n-5) -77*a(n-6) +248*a(n-7) +240*a(n-8) -1400*a(n-9) +564*a(n-10) +1220*a(n-11) +1358*a(n-12) -5000*a(n-13) +3019*a(n-14) +1209*a(n-15) +4104*a(n-16) -6840*a(n-17) +3995*a(n-18) +4214*a(n-19) -1497*a(n-20) -1140*a(n-21) -945*a(n-22) +1251*a(n-23) -2502*a(n-24) -60*a(n-25) -49*a(n-26) -272*a(n-27) +281*a(n-28) -376*a(n-29) -109*a(n-30) +103*a(n-31) +9*a(n-32) -27*a(n-33) -3*a(n-34) +6*a(n-35)
|
|
EXAMPLE
|
Some solutions for n=4
..0..2..1..0..1..2..0....0..1..1..1..0..3..0....0..2..0..3..0..3..0
..3..0..2..1..2..0..3....1..2..0..1..3..0..2....1..1..2..0..4..0..3
..0..4..0..3..0..4..0....2..0..3..1..0..2..1....2..0..2..2..0..4..0
..2..0..3..0..3..0..2....0..3..0..1..1..1..0....0..3..0..1..2..0..2
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|