A302637 Number of 4 X n 0..1 arrays with every element equal to 0, 1, 3 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

8, 10, 19, 33, 65, 149, 304, 643, 1343, 2880, 6038, 12805, 27015, 57283, 120917, 255898, 540904, 1144495, 2419416, 5117330, 10820901, 22886110, 48394996, 102347752, 216437366, 457724270, 967964774, 2047035882, 4328987213

Offset

1,1

Comments

Row 4 of A302635.

Links

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

Formula

Empirical: a(n) = a(n-1) +a(n-2) +2*a(n-3) +8*a(n-4) -6*a(n-5) -6*a(n-6) -13*a(n-7) -22*a(n-8) +7*a(n-9) +11*a(n-10) +28*a(n-11) +28*a(n-12) +2*a(n-13) -9*a(n-14) -27*a(n-15) -17*a(n-16) -2*a(n-17) +4*a(n-18) +10*a(n-19) +4*a(n-20) -2*a(n-21) -a(n-22) for n > 23.

Example

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

Crossrefs

Cf. A302635.

Sequence in context: A236653 A257274 A022322 * A230862 A281067 A070974

Adjacent sequences: A302634 A302635 A302636 * A302638 A302639 A302640

Keyword

nonn

Author

R. H. Hardin, Apr 10 2018

Status

approved