|
| |
|
|
A255988
|
|
Number of length n+4 0..1 arrays with at most one downstep in every 4 consecutive neighbor pairs.
|
|
1
|
|
|
|
26, 45, 80, 144, 256, 451, 796, 1413, 2510, 4448, 7872, 13943, 24718, 43817, 77636, 137540, 243712, 431899, 765360, 1356169, 2403034, 4258172, 7545592, 13370799, 23692770, 41983189, 74394040, 131826104, 233594880, 413927683, 733476228
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,1
|
|
|
COMMENTS
|
Column 4 of A255992.
|
|
|
LINKS
|
R. H. Hardin, Table of n, a(n) for n = 1..210
|
|
|
FORMULA
|
Empirical: a(n) = 2*a(n-1) -a(n-2) +3*a(n-4) -2*a(n-5).
Empirical g.f.: x*(26 - 7*x + 16*x^2 + 29*x^3 - 30*x^4) / (1 - 2*x + x^2 - 3*x^4 + 2*x^5). - Colin Barker, Jan 24 2018
|
|
|
EXAMPLE
|
Some solutions for n=4:
..1....1....0....1....0....0....1....1....1....1....0....0....0....1....1....1
..1....0....0....1....0....1....0....0....1....1....0....1....1....1....0....1
..1....0....0....0....1....1....0....0....1....1....0....0....0....1....0....0
..0....1....0....1....1....0....0....0....1....1....1....1....0....0....0....0
..1....1....1....1....0....0....0....1....1....0....1....1....0....0....1....1
..1....0....1....1....0....0....0....0....1....1....1....1....1....0....0....1
..1....0....1....1....0....1....1....0....0....1....1....0....1....1....0....1
..1....1....0....1....1....0....0....0....1....1....0....0....0....0....1....0
|
|
|
CROSSREFS
|
Cf. A255992.
Sequence in context: A217775 A260200 A178100 * A304673 A039458 A291672
Adjacent sequences: A255985 A255986 A255987 * A255989 A255990 A255991
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
R. H. Hardin, Mar 13 2015
|
|
|
STATUS
|
approved
|
| |
|
|
