cp's OEIS Frontend

A221509 Number of 3Xn arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, without consecutive moves in the same direction.

%I A221509 #5 Jul 23 2025 02:01:00
%S A221509 0,64,664,31663,730874,22664752,617892584,17782943460,499912745268,
%T A221509 14194927933912,401323009766448,11367289765226164,321716709992052606,
%U A221509 9108319376609834007,257833317722010551358,7299063007433073641077
%N A221509 Number of 3Xn arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, without consecutive moves in the same direction.
%C A221509 Row 3 of A221507
%e A221509 Some solutions for n=3
%e A221509 ..0..3..1....1..4..0....1..1..1....0..0..0....0..3..0....0..3..0....1..1..0
%e A221509 ..0..3..2....0..1..2....0..1..1....1..2..2....0..0..2....2..3..1....2..4..0
%e A221509 ..0..0..0....0..1..0....0..4..0....0..4..0....1..3..0....0..0..0....0..1..0
%K A221509 nonn
%O A221509 1,2
%A A221509 _R. H. Hardin_ Jan 18 2013