A303526 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 3, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

4, 6, 18, 37, 80, 286, 916, 2532, 7477, 24285, 76820, 235117, 731307, 2316410, 7294592, 22810317, 71569571, 225378484, 708826544, 2225946457, 6995090976, 21998860077, 69164809009, 217385283885, 683342646350, 2148402980261

Offset

1,1

Comments

Row 3 of A303525.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +3*a(n-2) +a(n-3) +30*a(n-4) -53*a(n-5) -102*a(n-6) +11*a(n-7) -227*a(n-8) +351*a(n-9) +784*a(n-10) -242*a(n-11) +351*a(n-12) -361*a(n-13) -1069*a(n-14) +577*a(n-15) +8*a(n-16) +28*a(n-17) +22*a(n-18) -11*a(n-19) -a(n-20) for n>21

Example

Some solutions for n=5
..0..0..0..1..0. .0..1..0..0..0. .0..0..1..0..1. .0..1..1..0..1
..0..1..1..1..0. .0..1..1..1..0. .1..1..1..0..1. .1..0..1..0..1
..0..1..0..1..0. .0..0..0..1..0. .1..0..0..0..1. .1..0..1..0..1

Crossrefs

Cf. A303525.

Sequence in context: A107390 A051253 A175955 * A064403 A235344 A060667

Adjacent sequences: A303523 A303524 A303525 * A303527 A303528 A303529

Keyword

nonn

Author

R. H. Hardin, Apr 25 2018

Status

approved