A268794 Number of nX4 0..2 arrays with some element plus some horizontally, vertically or antidiagonally adjacent neighbor totalling two exactly once.

36, 234, 950, 4800, 23994, 117062, 561116, 2652936, 12405748, 57490444, 264428454, 1208522850, 5493284922, 24851601802, 111963916212, 502590509990, 2248738675490, 10032298715910, 44640056867750, 198161794087570

Offset

1,1

Comments

Column 4 of A268798.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +19*a(n-2) +10*a(n-3) -122*a(n-4) -320*a(n-5) -295*a(n-6) +8*a(n-7) +176*a(n-8) +20*a(n-9) -98*a(n-10) -6*a(n-11) +43*a(n-12) -6*a(n-13) -11*a(n-14) +6*a(n-15) -a(n-16) for n>19

Example

Some solutions for n=4
..0..1..2..1. .2..2..1..2. .0..0..0..0. .1..2..2..2. .2..2..2..2
..2..2..2..2. .2..2..2..1. .0..1..0..1. .1..2..2..2. .1..2..2..1
..1..2..1..2. .1..2..2..2. .0..0..1..0. .2..2..2..1. .2..2..2..2
..2..2..2..1. .1..2..2..1. .1..0..0..0. .2..2..2..2. .1..1..2..2

Crossrefs

Cf. A268798.

Sequence in context: A166329 A264522 A297656 * A159921 A326347 A129149

Adjacent sequences: A268791 A268792 A268793 * A268795 A268796 A268797

Keyword

nonn

Author

R. H. Hardin, Feb 13 2016

Status

approved