cp's OEIS Frontend

A199707 Number of -n..n arrays x(0..4) of 5 elements with zero sum and no two neighbors equal.

%I A199707 #13 May 16 2018 11:19:49
%S A199707 14,200,892,2734,6504,13324,24394,41344,65788,99858,145596,205612,
%T A199707 282386,379036,498440,644218,819692,1028960,1275766,1564716,1899968,
%U A199707 2286630,2729288,3233528,3804374,4447920,5169588,5975974,6872944,7867572,8966146
%N A199707 Number of -n..n arrays x(0..4) of 5 elements with zero sum and no two neighbors equal.
%C A199707 Row 5 of A199704.
%H A199707 R. H. Hardin, <a href="/A199707/b199707.txt">Table of n, a(n) for n = 1..200</a>
%F A199707 Empirical: a(n)=2*a(n-1)-a(n-3)-2*a(n-5)+2*a(n-6)+a(n-8)-2*a(n-10)+a(n-11).
%F A199707 Empirical g.f.: 2*x*(7 + 86*x + 246*x^2 + 482*x^3 + 618*x^4 + 618*x^5 + 426*x^6 + 222*x^7 + 47*x^8 + 8*x^9) / ((1 - x)^5*(1 + x)^2*(1 + x^2)*(1 + x + x^2)). - _Colin Barker_, May 16 2018
%e A199707 Some solutions for n=5:
%e A199707 .-5...-1...-3...-4....4....1...-3...-1....5....0...-4....1....4....0....2....1
%e A199707 ..0....0....1...-3....1....3....1....2...-3...-2...-3...-2....0....2....3...-3
%e A199707 .-3...-4....2....3...-3....1...-4...-1...-1....5....1...-3...-3....4...-5....5
%e A199707 ..3....2...-5....1...-4...-5....2....1...-3...-2....2....4....1...-4....4....1
%e A199707 ..5....3....5....3....2....0....4...-1....2...-1....4....0...-2...-2...-4...-4
%Y A199707 Cf. A199704.
%K A199707 nonn
%O A199707 1,1
%A A199707 _R. H. Hardin_, Nov 09 2011