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A252575 Number of (1+2)X(n+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 1 2 5 6 or 7 and every 3X3 column and antidiagonal sum not equal to 1 2 5 6 or 7.

%I A252575 #6 Jun 02 2025 11:23:58
%S A252575 702,843,1069,1694,2985,5401,9936,18972,36144,68328,132259,254014,
%T A252575 483085,937293,1802438,3435781,6666327,12816791,24467952,47451918,
%U A252575 91181264,174286544,337798170,648685210,1241316959,2404367968,4614248202
%N A252575 Number of (1+2)X(n+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 1 2 5 6 or 7 and every 3X3 column and antidiagonal sum not equal to 1 2 5 6 or 7.
%C A252575 Row 1 of A252574
%H A252575 R. H. Hardin, <a href="/A252575/b252575.txt">Table of n, a(n) for n = 1..210</a>
%F A252575 Empirical: a(n) = 25*a(n-3) +a(n-4) -239*a(n-6) -23*a(n-7) +1103*a(n-9) +192*a(n-10) -2670*a(n-12) -696*a(n-13) +3918*a(n-15) +1086*a(n-16) -4034*a(n-18) -1050*a(n-19) +3218*a(n-21) +848*a(n-22) -1969*a(n-24) -472*a(n-25) +889*a(n-27) +177*a(n-28) -303*a(n-30) -63*a(n-31) +63*a(n-33) for n>43
%e A252575 Some solutions for n=4
%e A252575 ..1..3..2..1..3..2....3..1..1..0..0..1....2..3..2..2..3..2....2..2..2..3..0..3
%e A252575 ..0..0..2..0..0..1....3..1..2..2..1..2....0..0..1..0..0..2....1..1..0..1..1..3
%e A252575 ..2..0..0..2..0..0....2..2..1..2..2..1....2..0..0..2..0..0....0..0..2..0..3..2
%K A252575 nonn
%O A252575 1,1
%A A252575 _R. H. Hardin_, Dec 18 2014