A188358 T(n,k)=Number of arrangements of n+1 numbers x(i) in -k..k with the sum of x(i)*x(i+1) equal to zero.

5, 9, 15, 13, 45, 29, 17, 91, 117, 91, 21, 153, 257, 565, 197, 25, 231, 497, 1775, 1953, 627, 29, 325, 749, 4201, 7369, 9153, 1477, 33, 435, 1205, 8051, 22229, 49747, 37269, 4671, 37, 561, 1569, 14477, 45801, 181449, 262925, 173409, 11693, 41, 703, 2161

Offset: 1

Author

R. H. Hardin Mar 28 2011

Keywords

• nonn
• tabl

Comments

Table starts

.....5.......9.......13........17.........21..........25..........29

....15......45.......91.......153........231.........325.........435

....29.....117......257.......497........749........1205........1569

....91.....565.....1775......4201.......8051.......14477.......22583

...197....1953.....7369.....22229......45801......100885......163745

...627....9153....49747....181449.....480363.....1171345.....2295051

..1477...37269...262925...1264985....3882729....11535493....25217201

..4671..173409..1763151..10396729...40629247...136061137...355442823

.11693..766869.10536621..81850801..383541193..1540834589..4602176797

.36487.3589357.70819767.684867741.4033546763.18592832393.65556183495

Examples

			Some solutions for n=6 k=4
.-4...-1...-4....0....3....0...-1....0...-4...-1...-1...-1...-2...-1....1...-3
..0...-2...-3...-2...-4...-4...-3...-4....0...-1...-2...-3...-2....0...-2...-1
.-4....2....3....1....3....4...-3...-1....4....0....1....1...-2....4....1....1
..4...-1...-1....1....3....4....0...-2....0....0...-3...-4....1...-4...-4....2
..4....2....2....1....1....0....1....3...-2...-3...-1...-1...-2...-4....3...-3
..3....1...-2....0...-4....1...-3...-2....0...-1....0....2....1...-4....4...-1
.-4....4...-3...-1...-4....0....3...-3...-4....4....3....1...-2....4....2....1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..178

Crossrefs

Row 1 is A016813

Row 2 is A014634