login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Number of n X n integer arrays with each element equal to the number of horizontal and vertical neighbors differing from itself by exactly one.
0

%I #6 Apr 20 2020 19:41:08

%S 1,1,4,5,29,78,466,3907,52773,925875,25789942

%N Number of n X n integer arrays with each element equal to the number of horizontal and vertical neighbors differing from itself by exactly one.

%C Diagonal of A266081.

%e All solutions for n=4

%e ..0..2..3..2....0..0..0..0....0..0..0..0....2..3..2..0....0..0..0..0

%e ..0..3..4..3....2..3..2..0....0..0..0..0....3..4..3..0....0..2..3..2

%e ..0..2..3..2....3..4..3..0....0..0..0..0....2..3..2..0....0..3..4..3

%e ..0..0..0..0....2..3..2..0....0..0..0..0....0..0..0..0....0..2..3..2

%Y Cf. A266081.

%K nonn

%O 1,3

%A _R. H. Hardin_, Dec 20 2015