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A202909 Number of nX1 0..7 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor 1
1, 8, 64, 372, 1856, 9052, 45648, 235538, 1215616, 6233356, 31868448, 163014678, 834763824, 4276077566, 21900661172, 112149148911, 574278200480, 2940790043388, 15059692639376, 77120252989206, 394927990211792 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 1 of A202916

LINKS

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

FORMULA

Empirical: a(n) = 8*a(n-1) -28*a(n-2) +84*a(n-3) -126*a(n-4) +252*a(n-5) -210*a(n-6) +330*a(n-7) -165*a(n-8) +220*a(n-9) -66*a(n-10) +78*a(n-11) -13*a(n-12) +14*a(n-13) -a(n-14) +a(n-15)

EXAMPLE

Some solutions for n=4

..2....0....2....3....6....4....6....2....7....4....6....2....1....6....4....3

..6....5....2....3....6....7....6....3....7....4....6....6....4....7....4....3

..6....5....3....4....3....7....5....7....2....7....5....6....4....7....0....1

..4....2....3....4....0....3....0....7....0....7....2....2....0....0....0....0

CROSSREFS

Sequence in context: A224151 A225014 A228460 * A203437 A224132 A297376

Adjacent sequences:  A202906 A202907 A202908 * A202910 A202911 A202912

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 26 2011

STATUS

approved

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Last modified May 22 22:13 EDT 2022. Contains 353959 sequences. (Running on oeis4.)