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 A202040 Number of zero-sum n X n -1..1 arrays with every element unequal to at most two horizontal and vertical neighbors 0
 1, 19, 415, 31753, 6221993, 3573771563 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Diagonal of A202047 LINKS Table of n, a(n) for n=1..6. EXAMPLE Some solutions for n=4 .-1.-1..0.-1...-1..1..1.-1....0..0..0..1...-1..0..0..1...-1.-1..0.-1 ..1..0..0..0...-1.-1.-1.-1....1..0..0..1....0..0..0.-1....1..1..0..0 ..1..0..0..0....1..1..1..1....1.-1.-1..1....1..1..0.-1....1..1..1..1 ..0..1..1.-1....1..0..0.-1....0.-1.-1.-1....0..1..0.-1...-1.-1.-1..0 CROSSREFS Sequence in context: A252927 A172740 A172816 * A244765 A069612 A077716 Adjacent sequences: A202037 A202038 A202039 * A202041 A202042 A202043 KEYWORD nonn AUTHOR R. H. Hardin Dec 10 2011 STATUS approved

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Last modified September 11 21:59 EDT 2024. Contains 375839 sequences. (Running on oeis4.)