A188251 Number of arrangements of 5 nonzero numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero

12, 120, 548, 1504, 3292, 6376, 10564, 17040, 25436, 36808, 49556, 68912, 87804, 113384, 144644, 180912, 216044, 267160, 312404, 377904, 446588, 519976, 590420, 696576, 791164, 898456, 1016756, 1159280, 1278636, 1460936, 1598916, 1784224

Offset

1,1

Comments

Row 3 of A188249

Links

R. H. Hardin, Table of n, a(n) for n = 1..47

Example

Some solutions for n=4
..3...-2...-2...-3...-1...-1....1....1....4....1...-2...-4....2....2...-1...-3
.-3...-2....3...-4...-1...-3....3...-2....3...-2...-4...-2...-1....1...-1...-2
..2....3...-1....3....3....2....4...-4...-4...-1....2....1....2...-2....4....2
..3....1...-3...-2....2....1...-3....3...-2...-3...-4....3...-4...-4....3....2
..3...-1...-2...-3...-2....1....1....2....4....1...-2...-3...-3....2...-3...-3

Crossrefs

Sequence in context: A006953 A164877 A121032 * A093334 A001816 A354697

Adjacent sequences: A188248 A188249 A188250 * A188252 A188253 A188254

Keyword

nonn

Author

R. H. Hardin Mar 25 2011

Status

approved