A201872 - OEIS

%I #5 Mar 31 2012 12:36:45

%S 1,7,57,431,3373,27647,232969,1990383,17103271,147612131,1278588895,

%T 11110113949,96822737023,846090334081,7411911618255,65073276474339,

%U 572430700911207,5044195360234563,44516912275192801,393415480687909671

%N Number of zero-sum -7..7 arrays of n elements with first and second differences also in -7..7

%C Column 7 of A201873

%H R. H. Hardin, <a href="/A201872/b201872.txt">Table of n, a(n) for n = 1..208</a>

%e Some solutions for n=6

%e ..6...-1....3....0....0....1....7...-3....4....0....5...-1....5....4....6....0

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

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

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

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

%e .-6....4...-4....0....3....5...-5....6...-5....0...-7....7...-2...-6....1...-6

%K nonn

%O 1,2

%A _R. H. Hardin_ Dec 06 2011