A255113 - OEIS

A255113

Number of length n+6 0..2 arrays with at most one downstep in every n consecutive neighbor pairs.

2187, 5157, 7498, 10125, 14001, 19263, 25578, 33063, 41851, 52092, 63954, 77624, 93309, 111237, 131658, 154845, 181095, 210730, 244098, 281574, 323561, 370491, 422826, 481059, 545715, 617352, 696562, 783972, 880245, 986081, 1102218, 1229433

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Row 6 of A255107.

LINKS

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

FORMULA

Empirical: a(n) = (1/120)*n^5 + (3/8)*n^4 + (149/24)*n^3 + (2521/8)*n^2 + (56417/60)*n + 385 for n>4.

Empirical g.f.: x*(2187 - 7965*x + 9361*x^2 - 1248*x^3 - 4614*x^4 + 1405*x^5 + 1230*x^6 + 564*x^7 - 1354*x^8 + 435*x^9) / (1 - x)^6. - Colin Barker, Jan 24 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

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

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

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

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

CROSSREFS

Cf. A255107.

Sequence in context: A279070 A046320 A232926 * A255628 A232287 A219134

Adjacent sequences: A255110 A255111 A255112 * A255114 A255115 A255116

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 14 2015

STATUS

approved