A209681 - OEIS

%I #12 Oct 03 2025 15:25:08

%S 1,15,1549,11315839,268997909000,250057183645608263,

%T 431066310742284246294717,26767947592293738225917871688575,

%U 3047486118401281699024754722202652309976

%N Number of n X n 0..6 arrays with every element equal to a diagonal or antidiagonal reflection, and new values 0 upwards introduced in row major order.

%C Column 5 of A209684

%H R. H. Hardin, <a href="/A209681/b209681.txt">Table of n, a(n) for n = 1..46</a>

%e Some.solutions.for.n=3

%e ..0..0..1....0..1..0....0..1..2....0..0..1....0..1..1....0..1..2....0..1..2

%e ..1..1..0....0..1..1....1..1..1....0..0..1....1..2..0....1..2..0....1..1..0

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

%K nonn

%O 1,2

%A _R. H. Hardin_, Mar 11 2012