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A192691 Number of 1X4 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 1 zero-sum 4-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations) 1
2, 6, 15, 26, 45, 72, 105, 150, 206, 273, 353, 446, 560, 687, 834, 998, 1182, 1388, 1618, 1875, 2156, 2463, 2797, 3151, 3551, 3978, 4434, 4923, 5448, 6009, 6604, 7243, 7925, 8639, 9404, 10198, 11051, 11943, 12887, 13873, 14909, 16001, 17135, 18332, 19584 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column (1,4,n) of A192710

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

EXAMPLE

Some solutions for 1X4 <= 2*4^2

.-1..0..0..1...-2..0..0..2...-1.-1.-1..3...-2..0..1..1...-3.-1..0..4

CROSSREFS

Sequence in context: A091766 A269706 A293402 * A256313 A138621 A163061

Adjacent sequences:  A192688 A192689 A192690 * A192692 A192693 A192694

KEYWORD

nonn

AUTHOR

R. H. Hardin Jul 07 2011

STATUS

approved

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Last modified February 26 15:26 EST 2021. Contains 341632 sequences. (Running on oeis4.)