

A192707


Number of 7X2 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 7 zerosum 2vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations)


1



2, 6, 17, 39, 85, 167, 309, 546, 919, 1486, 2338, 3564, 5300, 7703, 11016, 15451, 21303, 28978, 38908, 51626, 67686, 87827, 112967, 144076, 182028, 228322, 284414, 351962, 432504, 528554, 642212, 776430, 933563, 1117263, 1331217, 1579771, 1865945
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OFFSET

1,1


COMMENTS

Column (7,2,n) of A192710


LINKS

R. H. Hardin, Table of n, a(n) for n = 1..163


EXAMPLE

Some solutions for 7X2 <= 2*4^2
.1..1...3..3...2..2...3..3...3..3...2..2...2..2...2..2...2..2...2..2
.1..1....0..0...1..1...1..1...1..1...1..1...1..1....0..0...2..2...2..2
.1..1....0..0...1..1....0..0...1..1...1..1....0..0....0..0...2..2....0..0
.1..1....0..0...1..1....0..0...1..1...1..1....0..0....0..0...1..1....0..0
.1..1....0..0....0..0....0..0...1..1...1..1....0..0....0..0...1..1....0..0
.1..1....0..0....0..0....0..0...1..1...1..1....0..0....0..0...1..1....0..0
..0..0....0..0....0..0....0..0....0..0...1..1....0..0....0..0....0..0....0..0


CROSSREFS

Sequence in context: A204450 A037261 A239234 * A252814 A072077 A229732
Adjacent sequences: A192704 A192705 A192706 * A192708 A192709 A192710


KEYWORD

nonn


AUTHOR

R. H. Hardin Jul 07 2011


STATUS

approved



