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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 2
1, 4, 1211, 6907736, 423503301834, 274342896958292170, 1877611081501313948217870, 135766460737448561825230968357842 (list; graph; refs; listen; history; text; internal format)
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

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Last modified September 30 07:52 EDT 2022. Contains 357104 sequences. (Running on oeis4.)