A198899 Number of n X n 0..4 arrays with values 0..4 introduced in row major order and no element equal to any horizontal or vertical neighbor

1, 4, 1211, 6907736, 423503301834, 274342896958292170, 1877611081501313948217870, 135766460737448561825230968357842

Offset

1,2

Comments

Diagonal of A198906

Links

Jean-François Alcover, Table of n, a(n) for n = 1..14

Example

Some solutions with values 0 to 4 for n=4
..0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1
..1..2..1..0....1..2..1..2....1..2..1..2....1..0..2..0....1..0..1..0
..0..1..3..4....2..3..0..1....3..0..2..0....3..4..0..3....2..1..0..3
..3..2..0..3....4..1..2..4....4..3..1..3....2..1..2..4....1..4..1..2

Mathematica

A198906 = Cases[Import["https://oeis.org/A198906/b198906.txt", "Table"], {_, _}][[All, 2]];
a[n_] := A198906[[2 n^2 - 2 n + 1]];
Table[a[n], {n, 1, 14}] (* Jean-François Alcover, Sep 23 2019 *)

Crossrefs

Sequence in context: A309979 A221383 A338104 * A350341 A253168 A160004

Adjacent sequences: A198896 A198897 A198898 * A198900 A198901 A198902

Keyword

nonn

Author

R. H. Hardin Oct 31 2011

Status

approved