login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

Number of zero-sum n X 2 -3..3 arrays with every element unequal to at most two horizontal and vertical neighbors.
1

%I #8 Dec 29 2023 23:06:33

%S 7,231,1587,17903,194633,2232183,25952953,305979795,3640250461,

%T 43624267941,525774918227,6366440653727,77388201173481,

%U 943784967491137,11542145313593503,141498452574240619,1738344524754583621

%N Number of zero-sum n X 2 -3..3 arrays with every element unequal to at most two horizontal and vertical neighbors.

%C Column 2 of A201958.

%H R. H. Hardin, <a href="/A201955/b201955.txt">Table of n, a(n) for n = 1..68</a>

%e Some solutions for n=4

%e ..2..3...-3.-3...-2.-3...-2..3...-2..1....2.-3....2.-3....2..0...-3.-1....1.-2

%e ..0..0....2..2....1..1....0..0...-2..0....1..1....3.-3....0.-1....3..0....0..0

%e .-2.-2...-1.-1....2..2....1..1....2..0....0..0....3..0....0.-1....3..0....0..0

%e .-2..1....3..1....0.-1...-1.-2....2.-1...-1..0...-2..0....3.-3...-2..0....3.-2

%Y Cf. A201958.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 06 2011