cp's OEIS Frontend

A200556 Number of -n..n arrays x(0..5) of 6 elements with zero sum and nonzero second differences.

%I A200556 #7 Jul 22 2025 15:52:24
%S A200556 72,1240,7254,26850,75792,178834,372150,705270,1242888,2067650,
%T A200556 3281874,5009232,7397868,10621792,14882672,20413220,27478160,36376230,
%U A200556 47443518,61054528,77624122,97610834,121518006,149895400,183343046,222512226
%N A200556 Number of -n..n arrays x(0..5) of 6 elements with zero sum and nonzero second differences.
%C A200556 Row 4 of A200553
%H A200556 R. H. Hardin, <a href="/A200556/b200556.txt">Table of n, a(n) for n = 1..200</a>
%F A200556 Empirical: a(n) = a(n-1) +a(n-2) +a(n-3) -2*a(n-4) -a(n-6) -a(n-7) -a(n-8) +3*a(n-9) +3*a(n-10) -a(n-11) -a(n-12) -a(n-13) -2*a(n-15) +a(n-16) +a(n-17) +a(n-18) -a(n-19)
%e A200556 Some solutions for n=3
%e A200556 ..0....2...-3....0...-3...-1....0....0....1....1...-2....1....2...-1...-3...-3
%e A200556 .-1...-3...-2....1...-3....2....1....0...-2....1....0....2....2....0....2....3
%e A200556 ..2....1....1....0....2....1....1...-2....1....3....1....0...-3....0...-2....1
%e A200556 .-3....3....1....3...-2...-2....0....2....3...-3....1...-3....1....2....0...-2
%e A200556 .-1...-1....3...-3....3....2....1...-2...-2....1....3....0...-1....1....3....3
%e A200556 ..3...-2....0...-1....3...-2...-3....2...-1...-3...-3....0...-1...-2....0...-2
%K A200556 nonn
%O A200556 1,1
%A A200556 _R. H. Hardin_ Nov 19 2011