A295209 Number of n X 4 0..1 arrays with each 1 horizontally or vertically adjacent to 2 or 3 1's.

1, 7, 27, 147, 916, 4938, 27208, 152236, 848992, 4746938, 26555583, 148468255, 830063597, 4640855585, 25946470239, 145065530889, 811058197498, 4534601269690, 25352811924120, 141746752099136, 792501412285360

Offset: 1

Author

R. H. Hardin, Nov 17 2017

Keywords

• nonn

Comments

Column 4 of A295213.

Examples

			Some solutions for n=7
..0..0..1..1. .1..1..1..1. .1..1..1..1. .1..1..0..0. .0..1..1..1
..0..0..1..1. .1..0..1..1. .1..0..1..1. .1..1..1..0. .1..1..1..1
..0..0..1..1. .1..1..1..1. .1..1..0..0. .1..0..1..0. .1..0..0..0
..0..0..1..1. .0..1..0..0. .0..1..1..0. .1..0..1..0. .1..1..1..0
..1..1..1..1. .0..1..1..0. .0..0..1..0. .1..0..1..0. .1..1..1..0
..1..1..0..1. .0..1..1..0. .0..1..1..0. .1..1..1..0. .0..0..1..1
..0..1..1..1. .0..0..0..0. .0..1..1..0. .1..1..0..0. .0..0..1..1
		

Links

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

Crossrefs

Cf. A295213.

Formula

Empirical: a(n) = 8*a(n-1) -17*a(n-2) +27*a(n-3) -66*a(n-4) +182*a(n-5) -188*a(n-6) -199*a(n-7) -22*a(n-8) +185*a(n-9) +385*a(n-10) +169*a(n-11) +49*a(n-12) +408*a(n-13) +516*a(n-14) -492*a(n-15) -1779*a(n-16) -408*a(n-17) +326*a(n-18) -331*a(n-19) +505*a(n-20) -310*a(n-21) +217*a(n-22) -111*a(n-23) +4*a(n-24) -16*a(n-25) +4*a(n-26) +4*a(n-27) -a(n-28).