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.

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

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

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

Adjacent sequences: A318343 A318344 A318345 * A318347 A318348 A318349

Keyword

nonn

Author

R. H. Hardin, Aug 24 2018

Status

approved