A069430 Half the number of 4 X n binary arrays with no path of adjacent 1's or adjacent 0's from top row to bottom row.

7, 88, 1074, 13002, 157058, 1896074, 22886754, 276246170, 3334295986, 40244915946, 485755429442, 5863058792506, 70767006224978, 854156391897098, 10309651065637602, 124437288171423322

Offset

1,1

Links

Table of n, a(n) for n=1..16.

Formula

Empirical (for n>=6): a(n) = 19*a(n-1) - 98*a(n-2) + 180*a(n-3) - 80*a(n-4) - 16*a(n-5). - Vaclav Kotesovec, Nov 28 2012

Empirical g.f.: x*(7 - 45*x + 88*x^2 - 40*x^3 - 8*x^4) / (1 - 19*x + 98*x^2 - 180*x^3 + 80*x^4 + 16*x^5). - Colin Barker, Oct 12 2017

Crossrefs

Cf. 2 X n A000079, n X 1 A000225, vertical path of 1 A069361-A069395, vertical paths of 0+1 A069396-A069416, vertical path of 1 not 0 A069417-A069428, no vertical paths A069429-A069447, no horizontal or vertical paths A069448-A069452.

Sequence in context: A155465 A296735 A137143 * A020564 A006291 A220193

Adjacent sequences: A069427 A069428 A069429 * A069431 A069432 A069433

Keyword

nonn

Author

R. H. Hardin, Mar 22 2002

Status

approved