|
|
A250588
|
|
Number of (n+1)X(4+1) 0..2 arrays with nondecreasing max(x(i,j),x(i,j-1)) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.
|
|
2
|
|
|
2375, 14983, 79415, 379397, 1686514, 7120483, 29029369, 115191907, 448833569, 1723204432, 6551633555, 24709506002, 92716016604, 346413672235, 1291010570063, 4801025640575, 17833372282529, 66175132547455
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Appears to satisfy the same recurrence relation as A250636.
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 17*a(n-1) -101*a(n-2) +110*a(n-3) +1466*a(n-4) -6607*a(n-5) +2715*a(n-6) +50990*a(n-7) -125338*a(n-8) -69069*a(n-9) +724777*a(n-10) -770521*a(n-11) -1528585*a(n-12) +4147071*a(n-13) -616996*a(n-14) -8587972*a(n-15) +9209705*a(n-16) +6258473*a(n-17) -18241543*a(n-18) +5925196*a(n-19) +15364973*a(n-20) -15498239*a(n-21) -2690737*a(n-22) +12025570*a(n-23) -4880027*a(n-24) -3407185*a(n-25) +3581843*a(n-26) -420145*a(n-27) -810850*a(n-28) +400975*a(n-29) -4790*a(n-30) -48700*a(n-31) +15025*a(n-32) -1500*a(n-33) for n > 35.
|
|
EXAMPLE
|
Some solutions for n=3:
..1..0..0..0..1....1..0..0..0..0....0..0..2..1..1....0..0..1..1..2
..0..1..1..1..1....0..1..1..1..2....0..2..1..2..1....0..0..1..1..2
..1..0..1..2..2....2..2..2..2..2....2..0..2..1..2....0..1..2..2..2
..0..2..2..1..2....2..2..2..2..2....0..2..0..2..1....2..1..2..2..2
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|