cp's OEIS Frontend

A189273 Number of n X n array permutations with each element not moved or moved diagonally or antidiagonally by one.

%I A189273 #15 Sep 03 2024 15:07:58
%S A189273 1,4,45,2704,670480,787195249,4145792570105,101143260268999524,
%T A189273 11280706205128114909440,5796399045731034830898691089,
%U A189273 13683583940408484626053574835068160,148672374145154580465126584170730657054929,7431065990498975549840519048937892773708604741833
%N A189273 Number of n X n array permutations with each element not moved or moved diagonally or antidiagonally by one.
%C A189273 a(n) is a perfect square when n is even. - _Pontus von Brömssen_, Sep 03 2024
%H A189273 Pontus von Brömssen, <a href="/A189273/b189273.txt">Table of n, a(n) for n = 1..20</a>
%e A189273 Some solutions for 3 X 3:
%e A189273 ..0..3..4....0..5..4....4..3..2....0..3..2....0..3..4....0..5..2....0..3..2
%e A189273 ..7..2..1....7..2..1....1..0..7....1..8..7....1..2..7....7..6..1....7..4..1
%e A189273 ..6..5..8....6..3..8....6..5..8....6..5..4....6..5..8....4..3..8....6..5..8
%Y A189273 Diagonal of A189280.
%K A189273 nonn
%O A189273 1,2
%A A189273 _R. H. Hardin_, Apr 19 2011
%E A189273 More terms from _Pontus von Brömssen_, Sep 03 2024