

A235283


Number of (n+1) X (2+1) 0..3 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 4 (constant stress 1 X 1 tilings).


1



40, 68, 104, 188, 304, 572, 968, 1868, 3280, 6428, 11624, 22988, 42544, 84572, 159368, 317708, 607120, 1212188, 2341544, 4678988, 9113584, 18218972, 35712968, 71409548, 140660560, 281288348, 556133864, 1112202188, 2205141424, 4410151772
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OFFSET

1,1


LINKS

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


FORMULA

Empirical: a(n) = 3*a(n1) + 3*a(n2)  15*a(n3) + 4*a(n4) + 18*a(n5)  12*a(n6).
Empirical g.f.: 4*x*(10  13*x  55*x^2 + 68*x^3 + 72*x^4  84*x^5) / ((1  x)*(1  2*x)*(1  2*x^2)*(1  3*x^2)).  Colin Barker, Oct 18 2018


EXAMPLE

Some solutions for n=4:
..0..1..0....3..2..3....0..1..0....1..3..2....0..1..0....0..2..0....0..3..0
..3..0..3....0..3..0....3..0..3....2..0..3....3..0..3....3..1..3....2..1..2
..2..3..2....3..2..3....1..2..1....0..2..1....0..1..0....0..2..0....0..3..0
..3..0..3....0..3..0....3..0..3....2..0..3....3..0..3....3..1..3....1..0..1
..2..3..2....2..1..2....0..1..0....0..2..1....1..2..1....0..2..0....0..3..0


CROSSREFS

Column 2 of A235289.
Sequence in context: A205066 A232870 A338373 * A134216 A043156 A039333
Adjacent sequences: A235280 A235281 A235282 * A235284 A235285 A235286


KEYWORD

nonn


AUTHOR

R. H. Hardin, Jan 05 2014


STATUS

approved



