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A192699
Number of 2X4 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 2 zero-sum 4-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations)
1
2, 11, 48, 166, 459, 1125, 2426, 4871, 9028, 15919, 26530, 42795, 66234, 100066, 146708, 211012, 295903, 409009, 555042, 743702, 980297, 1279677, 1648401, 2106146, 2660304, 3336122, 4142715, 5114735, 6259510, 7619959, 9210010
OFFSET
1,1
COMMENTS
Column (2,4,n) of A192710
LINKS
EXAMPLE
Some solutions for 2X4 <= 2*4^2
.-3.-1..1..3...-3.-1..2..2...-1.-1..0..2...-2.-1..0..3...-2.-2..1..3
.-3..1..1..1...-2.-1..0..3....0..0..0..0...-2..0..0..2...-2..0..0..2
CROSSREFS
Sequence in context: A050929 A019005 A112288 * A003442 A054894 A270662
KEYWORD
nonn
AUTHOR
R. H. Hardin Jul 07 2011
STATUS
approved