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A318346
Number of nX4 0..1 arrays with every element unequal to 0, 1, 3 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
1
5, 7, 13, 14, 29, 55, 106, 220, 432, 885, 1788, 3642, 7416, 15082, 30713, 62570, 127441, 259671, 529160, 1078183, 2197318, 4477498, 9124533, 18594318, 37892248, 77219600, 157363288, 320686910, 653519695, 1331791431, 2714024976, 5530847648
OFFSET
1,1
COMMENTS
Column 4 of A318350.
LINKS
FORMULA
Empirical: a(n) = a(n-1) +2*a(n-3) +2*a(n-4) +5*a(n-5) +4*a(n-7) +3*a(n-8) +a(n-9) -9*a(n-10) -11*a(n-11) -41*a(n-12) -29*a(n-13) -52*a(n-14) +4*a(n-15) +7*a(n-16) +37*a(n-17) +13*a(n-18) +28*a(n-19) +32*a(n-20) -4*a(n-21) +39*a(n-22) +8*a(n-23) +6*a(n-24) +37*a(n-25) -23*a(n-26) -3*a(n-27) -20*a(n-28) -24*a(n-29) -12*a(n-30) -8*a(n-31) -4*a(n-32) +4*a(n-33) +8*a(n-35) -4*a(n-36) +4*a(n-37) for n>45
EXAMPLE
Some solutions for n=5
..0..0..0..0. .0..0..0..1. .0..0..0..0. .0..0..0..0. .0..0..0..0
..0..0..0..0. .0..0..0..0. .0..0..0..0. .1..0..1..0. .0..0..0..0
..0..0..0..0. .0..0..0..0. .0..0..0..0. .1..0..0..0. .0..0..1..0
..0..0..0..0. .0..0..0..0. .0..1..0..0. .0..1..1..0. .0..0..0..0
..0..0..0..0. .1..0..0..0. .0..0..0..0. .1..1..1..1. .0..0..0..0
CROSSREFS
Cf. A318350.
Sequence in context: A164122 A166163 A249801 * A342715 A050079 A372081
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 24 2018
STATUS
approved