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A232078
Number of (2+1) X (n+1) 0..1 arrays with every element equal to some horizontal, diagonal or antidiagonal neighbor, with top left element zero.
1
11, 87, 520, 3681, 26587, 189404, 1348429, 9607995, 68462448, 487805049, 3475683907, 24764857724, 176453944877, 1257264924795, 8958230513184, 63828946109201, 454792310901883, 3240474086774308, 23088939844648997
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) + 11*a(n-2) + 23*a(n-3) + 45*a(n-4) + 10*a(n-5) + a(n-6) - 3*a(n-7) - 2*a(n-8).
Empirical g.f.: x*(11 + 32*x - 36*x^2 - 129*x^3 - 34*x^4 - 7*x^5 + 8*x^6 + 6*x^7) / (1 - 5*x - 11*x^2 - 23*x^3 - 45*x^4 - 10*x^5 - x^6 + 3*x^7 + 2*x^8). - Colin Barker, Oct 03 2018
EXAMPLE
Some solutions for n=6:
..0..0..1..0..0..0..0....0..0..0..1..1..1..1....0..0..0..0..0..0..0
..0..1..1..0..1..1..1....0..0..1..1..1..0..1....0..1..1..1..0..1..0
..1..0..0..1..1..1..1....0..1..0..1..0..1..0....1..0..0..0..1..1..1
CROSSREFS
Row 2 of A232076.
Sequence in context: A298253 A277465 A357535 * A016222 A081013 A163616
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 17 2013
STATUS
approved