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Number of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 0 3 4 6 or 7 and every 3X3 column and antidiagonal sum not equal to 0 3 4 6 or 7
1

%I #4 Dec 19 2014 11:27:36

%S 572,687,1189,2230,4382,8697,17046,34424,69196,136906,278002,561138,

%T 1119260,2283480,4624958,9291788,19034708,38667770,78183568,160738190,

%U 327379782,665660970,1372806636,2802341926,5725582074,11839463788

%N Number of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 0 3 4 6 or 7 and every 3X3 column and antidiagonal sum not equal to 0 3 4 6 or 7

%C Column 1 of A252640

%H R. H. Hardin, <a href="/A252633/b252633.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 25*a(n-3) -222*a(n-6) +815*a(n-9) -1085*a(n-12) +696*a(n-15) -756*a(n-18) for n>24

%e Some solutions for n=4

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

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 19 2014