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A192708 Number of 8X2 integer matrices with each row summing to zero, row elements in nondecreasing order, rows in lexicographically nondecreasing order, and the sum of squares of the elements <= 2*n^2 (number of collections of 8 zero-sum 2-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations) 1
2, 6, 18, 43, 97, 199, 385, 707, 1235, 2072, 3383, 5336, 8218, 12341, 18215, 26362, 37488, 52464, 72546, 98944, 133305, 177633, 234514, 306557, 397175, 510188, 650637, 823774, 1035586, 1293255, 1606070, 1982596, 2433768, 2972209, 3612860 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column (8,2,n) of A192710

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..125

EXAMPLE

Some solutions for 8X2 <= 2*4^2

.-1..1...-2..2...-1..1...-1..1...-1..1...-1..1...-3..3...-3..3...-2..2...-1..1

.-1..1...-1..1...-1..1....0..0...-1..1...-1..1...-1..1...-2..2...-2..2...-1..1

.-1..1...-1..1....0..0....0..0...-1..1...-1..1...-1..1...-1..1...-1..1...-1..1

..0..0...-1..1....0..0....0..0...-1..1...-1..1...-1..1...-1..1...-1..1...-1..1

..0..0...-1..1....0..0....0..0...-1..1...-1..1...-1..1...-1..1...-1..1...-1..1

..0..0....0..0....0..0....0..0...-1..1...-1..1...-1..1....0..0...-1..1...-1..1

..0..0....0..0....0..0....0..0....0..0...-1..1....0..0....0..0...-1..1...-1..1

..0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0...-1..1

CROSSREFS

Sequence in context: A195584 A225316 A272934 * A233531 A320303 A319415

Adjacent sequences:  A192705 A192706 A192707 * A192709 A192710 A192711

KEYWORD

nonn

AUTHOR

R. H. Hardin Jul 07 2011

STATUS

approved

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Last modified January 19 00:22 EST 2022. Contains 350464 sequences. (Running on oeis4.)