A232317 Number of (1+1)X(n+1) 0..1 arrays with every element equal to some horizontal or antidiagonal neighbor, with top left element zero

2, 5, 16, 52, 169, 549, 1784, 5797, 18837, 61210, 198899, 646313, 2100164, 6824385, 22175521, 72058322, 234150159, 760860029, 2472379204, 8033880997, 26105721877, 84829326570, 275648943179, 895708394113, 2910562681764, 9457737786265

Offset

1,1

Comments

Row 1 of A232316

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +a(n-2) -2*a(n-4) for n>5.

Empirical: G.f.: 2*x -x^2*(-5-x+x^2+3*x^3) / ( 1-3*x-x^2+2*x^4 ). - R. J. Mathar, Nov 24 2013

Example

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

Crossrefs

Sequence in context: A234843 A011819 A148390 * A148391 A337268 A148392

Adjacent sequences: A232314 A232315 A232316 * A232318 A232319 A232320

Keyword

nonn

Author

R. H. Hardin, Nov 22 2013

Status

approved