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A258736 Number of length n+6 0..3 arrays with at most one downstep in every n consecutive neighbor pairs. 1
16384, 43681, 68120, 98676, 149960, 228081, 331584, 465580, 635992, 849708, 1114752, 1440474, 1837760, 2319263, 2899656, 3595908, 4427584, 5417170, 6590424, 7976754, 9609624, 11526989, 13771760, 16392300, 19442952, 22984600, 27085264 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Row 6 of A258730.
LINKS
FORMULA
Empirical: a(n) = (1/5040)*n^7 + (1/72)*n^6 + (149/360)*n^5 + (239/36)*n^4 + (297247/720)*n^3 + (187297/72)*n^2 + (178036/35)*n + 2212 for n>4.
Empirical g.f.: x*(16384 - 87391*x + 177424*x^2 - 140720*x^3 - 31344*x^4 + 116775*x^5 - 39024*x^6 - 13988*x^7 - 31192*x^8 + 58867*x^9 - 31680*x^10 + 5890*x^11) / (1 - x)^8. - Colin Barker, Jan 26 2018
EXAMPLE
Some solutions for n=4:
..2....1....1....2....0....0....2....1....3....0....2....1....0....3....0....0
..2....0....1....0....0....0....0....1....3....1....1....1....2....3....0....0
..0....1....2....0....2....2....0....0....2....0....1....2....3....0....2....3
..0....1....0....0....2....2....0....1....2....0....3....0....3....0....2....0
..2....1....0....0....2....0....0....2....2....3....3....2....1....0....0....0
..2....2....0....1....2....0....2....2....2....3....1....2....1....0....0....1
..3....3....2....2....2....0....0....3....0....0....1....2....1....1....0....3
..1....3....1....2....0....0....1....3....2....0....1....0....2....3....1....3
..3....3....1....3....2....1....2....1....2....3....3....0....3....1....2....0
..3....2....1....0....3....0....2....1....3....3....1....0....2....1....3....0
CROSSREFS
Cf. A258730.
Sequence in context: A212936 A069275 A216074 * A255666 A220767 A115348
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jun 08 2015
STATUS
approved

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Last modified March 28 09:02 EDT 2024. Contains 371237 sequences. (Running on oeis4.)