cp's OEIS Frontend

A203288 Number of arrays of 2n nondecreasing integers in -5..5 with sum zero and equal numbers greater than zero and less than zero.

%I A203288 #7 Jul 22 2025 17:06:10
%S A203288 6,35,154,544,1614,4206,9880,21363,43136,82267,149456,260438,437670,
%T A203288 712512,1127794,1741011,2628022,3887553,5646312,8065104,11345704,
%U A203288 15738920,21553576,29166921,39036102,51711323,67850258,88234392
%N A203288 Number of arrays of 2n nondecreasing integers in -5..5 with sum zero and equal numbers greater than zero and less than zero.
%C A203288 Column 5 of A203291
%H A203288 R. H. Hardin, <a href="/A203288/b203288.txt">Table of n, a(n) for n = 1..145</a>
%F A203288 Empirical: a(n) = 4*a(n-1) -4*a(n-2) -2*a(n-3) +3*a(n-4) +7*a(n-6) -10*a(n-7) +a(n-8) -a(n-10) +10*a(n-11) -7*a(n-12) -3*a(n-14) +2*a(n-15) +4*a(n-16) -4*a(n-17) +a(n-18)
%e A203288 Some solutions for n=3
%e A203288 .-5...-3...-3...-3...-5...-5...-3...-5...-5...-3...-4...-5...-4...-5...-5...-3
%e A203288 .-4...-1...-2...-3...-4...-5...-2....0...-2...-3...-2...-4...-4...-5...-3...-3
%e A203288 .-2...-1....0...-3...-2...-4...-2....0...-1...-1...-1...-1...-3...-2...-2...-2
%e A203288 ..1....1....0....2....3....4....1....0....2....1....2....1....3....4....2....2
%e A203288 ..5....2....1....2....3....5....1....0....3....2....2....4....4....4....3....3
%e A203288 ..5....2....4....5....5....5....5....5....3....4....3....5....4....4....5....3
%K A203288 nonn
%O A203288 1,1
%A A203288 _R. H. Hardin_ Dec 31 2011