A192712 Number of 11X2 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 11 zero-sum 2-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations)

2, 6, 19, 51, 126, 285, 604, 1208, 2310, 4237, 7513, 12885, 21536, 35072, 55893, 87271, 133793, 201572, 299171, 437546, 631447, 900231, 1268643, 1768448, 2440754, 3336495, 4520239, 6073339, 8095214, 10708816, 14066591, 18351402, 23788458

Offset

1,1

Comments

Column (11,2,n) of A192710

Links

R. H. Hardin, Table of n, a(n) for n = 1..75

Example

Some solutions for 11X2 <= 2*4^2
.-1..1...-3..3...-3..3...-3..3...-2..2...-1..1...-2..2...-3..3...-2..2...-3..3
..0..0...-2..2...-1..1...-2..2...-2..2...-1..1...-1..1...-1..1...-2..2...-1..1
..0..0...-1..1...-1..1...-1..1...-1..1...-1..1...-1..1...-1..1...-2..2...-1..1
..0..0...-1..1...-1..1...-1..1...-1..1....0..0...-1..1...-1..1...-1..1....0..0
..0..0....0..0...-1..1...-1..1...-1..1....0..0...-1..1....0..0....0..0....0..0
..0..0....0..0....0..0....0..0...-1..1....0..0...-1..1....0..0....0..0....0..0
..0..0....0..0....0..0....0..0...-1..1....0..0...-1..1....0..0....0..0....0..0
..0..0....0..0....0..0....0..0....0..0....0..0...-1..1....0..0....0..0....0..0
..0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0
..0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0
..0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0

Crossrefs

Sequence in context: A192709 A034533 A192711 * A214948 A192713 A014559

Adjacent sequences: A192709 A192710 A192711 * A192713 A192714 A192715

Keyword

nonn

Author

R. H. Hardin Jul 07 2011

Status

approved