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 A252401 Number of (n+2) X (2+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 2 3 4 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 2 3 4 6 or 7. 1

%I #6 Mar 07 2022 13:59:47

%S 661,442,688,1224,2414,5061,10129,21427,46070,93671,200430,433693,

%T 885001,1898578,4117127,8413072,18067521,39215676,80182777,172284095,

%U 374104916,765132570,1644394003,3571453244,7305450882,15702421450,34107480805

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

%C Column 2 of A252407.

%H R. H. Hardin, <a href="/A252401/b252401.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 16*a(n-3) -74*a(n-6) +141*a(n-9) -235*a(n-12) +206*a(n-15) -72*a(n-18) +16*a(n-21) +4*a(n-24) -a(n-27) for n>31.

%e Some solutions for n=4

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

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

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

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

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

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

%Y Cf. A252407.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 17 2014

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Last modified September 25 02:38 EDT 2023. Contains 365582 sequences. (Running on oeis4.)