A212784 - OEIS

%I #6 May 27 2012 07:27:10

%S 8,66,350,1134,3010,6724,13544,24870,42952,70060,109638,165098,241342,

%T 343074,476992,649304,868684,1143156,1483630,1900056,2405958,3013428,

%U 3738744,4596484,5605944,6784266,8154174,9735586,11554762,13634780

%N Half the number of 0..n arrays of length 5 with second differences nonzero

%C Row 3 of A212782

%H R. H. Hardin, <a href="/A212784/b212784.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) +2*a(n-2) -2*a(n-4) -4*a(n-5) +a(n-6) +3*a(n-7) +3*a(n-8) +a(n-9) -4*a(n-10) -2*a(n-11) +2*a(n-13) +a(n-14) -a(n-15)

%e Some solutions for n=5

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ May 27 2012