A250272 - OEIS

%I #4 Nov 16 2014 06:58:34

%S 4,20,52,240,984,4412,20252,91808,406748,1759740,7455484,31056840,

%T 127719296,520368940,2106440916,8489650480,34118389900,136865613068,

%U 548408972596,2195889958776,8788865312160,35167823753468,140699850287804

%N Number of length n+1 0..3 arrays with the sum of the squares of adjacent differences multiplied by some arrangement of +-1 equal to zero

%C Column 3 of A250277

%H R. H. Hardin, <a href="/A250272/b250272.txt">Table of n, a(n) for n = 1..55</a>

%F Empirical: a(n) = 22*a(n-1) -221*a(n-2) +1348*a(n-3) -5594*a(n-4) +16756*a(n-5) -37474*a(n-6) +63792*a(n-7) -83421*a(n-8) +83878*a(n-9) -64369*a(n-10) +37052*a(n-11) -15496*a(n-12) +4448*a(n-13) -784*a(n-14) +64*a(n-15) for n>18

%e Some solutions for n=6

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

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

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 16 2014