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Number of nX7 integer arrays with each element equal to the number of horizontal and antidiagonal neighbors equal to itself.
1

%I #4 Dec 20 2015 06:57:37

%S 1,4,27,75,486,2208,10708,53384,255936,1264666,6155158,30091959,

%T 147181798,718659407,3513986897,17168832194,83908881411,410071803548,

%U 2003955083279,9793599928641,47860794887575,233897163096237

%N Number of nX7 integer arrays with each element equal to the number of horizontal and antidiagonal neighbors equal to itself.

%C Column 7 of A266012.

%H R. H. Hardin, <a href="/A266011/b266011.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) +12*a(n-2) +35*a(n-3) +11*a(n-4) -18*a(n-5) -253*a(n-6) -68*a(n-7) -142*a(n-8) +353*a(n-9) +167*a(n-10) +285*a(n-11) +263*a(n-12) -218*a(n-13) +383*a(n-14) -581*a(n-15) +430*a(n-16) -544*a(n-17) -75*a(n-18) -27*a(n-19) -240*a(n-20) +501*a(n-21) -210*a(n-22) +252*a(n-23) -144*a(n-24) for n>28

%e Some solutions for n=4

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

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

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

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

%Y Cf. A266012.

%K nonn

%O 1,2

%A _R. H. Hardin_, Dec 20 2015