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A258734 Number of length n+4 0..3 arrays with at most one downstep in every n consecutive neighbor pairs. 1
1024, 3136, 6552, 12549, 21860, 35704, 55660, 83758, 122584, 175400, 246280, 340263, 463524, 623564, 829420, 1091896, 1423816, 1840300, 2359064, 3000745, 3789252, 4752144, 5921036, 7332034, 9026200, 11050048, 13456072, 16303307 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 4 of A258730.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = (1/5040)*n^7 + (1/90)*n^6 + (19/72)*n^5 + (59/18)*n^4 + (47527/720)*n^3 + (14522/45)*n^2 + (39961/84)*n + 100 for n>2.

Empirical g.f.: x*(1024 - 5056*x + 10136*x^2 - 9403*x^3 + 988*x^4 + 7460*x^5 - 8940*x^6 + 5164*x^7 - 1576*x^8 + 204*x^9) / (1 - x)^8. - Colin Barker, Jan 26 2018

EXAMPLE

Some solutions for n=4:

..2....1....3....0....1....0....0....0....0....3....0....2....1....2....2....2

..1....3....3....2....1....2....2....1....0....3....0....2....0....3....3....0

..2....0....2....0....0....0....3....3....1....0....3....2....1....0....0....0

..2....0....2....2....1....0....0....0....1....0....1....2....2....2....1....0

..3....0....2....2....1....1....0....0....0....0....2....2....2....2....2....1

..0....3....3....2....2....1....0....1....1....0....2....2....3....2....2....1

..1....2....3....1....2....1....3....1....1....2....3....3....0....1....2....1

..3....3....2....1....3....3....0....2....2....1....1....1....2....1....0....1

CROSSREFS

Cf. A258730.

Sequence in context: A223065 A298607 A195093 * A195234 A257650 A255664

Adjacent sequences:  A258731 A258732 A258733 * A258735 A258736 A258737

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 08 2015

STATUS

approved

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Last modified May 19 04:20 EDT 2022. Contains 353826 sequences. (Running on oeis4.)