%I #7 Apr 18 2023 09:27:36
%S 154,2134,27806,372150,5012084,68263780,936121220,12911643944,
%T 178893425570,2488110363432,34717386812304,485767803378730,
%U 6813227225653584,95761068651953630,1348433104134460586
%N Number of -7..7 arrays x(0..n+1) of n+2 elements with zero sum and nonzero second differences.
%C Column 7 of A200553.
%H R. H. Hardin, <a href="/A200552/b200552.txt">Table of n, a(n) for n = 1..83</a>
%e Some solutions for n=3
%e .-6....1...-7....5....0...-6....4....1....1....0....1...-4....7...-6...-3....2
%e ..2...-3....5...-4....2....5...-6...-2....3...-1....2....0...-1....6...-4....0
%e ..1...-2....2...-1...-4....4...-2....5....1....5....1....3....4...-1...-2....3
%e ..2....1...-3....5...-4....2....4...-3....2...-2...-5....2...-3....1....5...-5
%e ..1....3....3...-5....6...-5....0...-1...-7...-2....1...-1...-7....0....4....0
%Y Cf. A200553.
%K nonn
%O 1,1
%A _R. H. Hardin_, Nov 19 2011
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