|
|
A255664
|
|
Number of length n+4 0..3 arrays with at most two downsteps in every n consecutive neighbor pairs
|
|
1
|
|
|
1024, 4096, 16128, 54560, 155144, 385738, 864924, 1788660, 3467296, 6376160, 11223728, 19042353, 31307660, 50094036, 78275176, 119780409, 179919544, 265791268, 386792720, 555250782, 787198896, 1103326862, 1530135124
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = (1/39916800)*n^11 + (1/362880)*n^10 + (11/80640)*n^9 + (461/120960)*n^8 + (141551/1209600)*n^7 + (36127/17280)*n^6 + (14049449/725760)*n^5 + (18041057/362880)*n^4 + (35402863/302400)*n^3 + (1423187/10080)*n^2 + (1020871/3080)*n + 163 for n>2
|
|
EXAMPLE
|
Some solutions for n=4
..2....2....0....1....2....1....3....2....3....3....2....3....0....1....0....3
..2....3....1....0....1....0....0....0....1....2....1....1....0....3....2....3
..2....0....0....1....0....0....3....1....1....0....0....2....3....1....3....3
..3....1....2....2....2....2....0....0....1....0....0....1....0....0....2....2
..3....0....2....1....3....1....3....0....2....1....1....2....0....0....1....0
..0....1....2....0....0....3....0....2....1....2....0....3....0....3....2....1
..3....1....2....0....3....0....1....3....0....0....2....2....1....1....3....3
..1....1....3....3....2....0....1....2....3....1....2....2....0....1....0....2
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|