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A188115
Number of strictly increasing arrangements of n nonzero numbers in -n..n with sum zero
1
0, 2, 2, 8, 16, 52, 152, 484, 1536, 5064, 16946, 57528, 197616, 686588, 2407538, 8510428, 30300268, 108575996, 391301260, 1417520988, 5159160792, 18857230104, 69193592020, 254802169904, 941383915572, 3488574124056, 12964318919492
OFFSET
1,2
COMMENTS
Column 2 of A188122
LINKS
EXAMPLE
Some solutions for n=6
.-5...-5...-6...-6...-5...-6...-6...-6...-6...-5...-6...-4...-6...-6...-5...-6
.-4...-4...-4...-5...-4...-5...-5...-3...-4...-3...-5...-3...-4...-2...-4...-4
.-1...-1...-2...-1...-2...-4...-3...-2...-1...-1...-1...-1...-2...-1...-2...-1
..1....1....2....3....2....4....3....2....2....2....2....1....3....1....1....2
..4....3....4....4....4....5....5....3....3....3....4....2....4....2....4....4
..5....6....6....5....5....6....6....6....6....4....6....5....5....6....6....5
CROSSREFS
Sequence in context: A109190 A016120 A367071 * A085542 A239682 A009725
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 21 2011
STATUS
approved