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A203288 Number of arrays of 2n nondecreasing integers in -5..5 with sum zero and equal numbers greater than zero and less than zero 1

%I #5 Mar 31 2012 12:36:56

%S 6,35,154,544,1614,4206,9880,21363,43136,82267,149456,260438,437670,

%T 712512,1127794,1741011,2628022,3887553,5646312,8065104,11345704,

%U 15738920,21553576,29166921,39036102,51711323,67850258,88234392

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

%C Column 5 of A203291

%H R. H. Hardin, <a href="/A203288/b203288.txt">Table of n, a(n) for n = 1..145</a>

%F 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 Some solutions for n=3

%e .-5...-3...-3...-3...-5...-5...-3...-5...-5...-3...-4...-5...-4...-5...-5...-3

%e .-4...-1...-2...-3...-4...-5...-2....0...-2...-3...-2...-4...-4...-5...-3...-3

%e .-2...-1....0...-3...-2...-4...-2....0...-1...-1...-1...-1...-3...-2...-2...-2

%e ..1....1....0....2....3....4....1....0....2....1....2....1....3....4....2....2

%e ..5....2....1....2....3....5....1....0....3....2....2....4....4....4....3....3

%e ..5....2....4....5....5....5....5....5....3....4....3....5....4....4....5....3

%K nonn

%O 1,1

%A _R. H. Hardin_ Dec 31 2011

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