A202079 Number of arrays of 8 integers in -n..n with sum zero and the sum of every adjacent pair being odd.

12, 524, 5832, 34632, 142692, 462436, 1264272, 3044496, 6644604, 13406844, 25370840, 45516120, 78055380, 128783316, 205485856, 318414624, 480831468, 709627884, 1026024168, 1456353128, 2032933188, 2795035716, 3789951408

Offset: 1

Author

R. H. Hardin, Dec 10 2011

Keywords

• nonn

Comments

Row 6 of A202076.

Examples

			Some solutions for n=3:
.-3...-2....1...-3....2....2....1....1...-2....2....3...-2....1...-3....3....0
..0....1...-2....0....3....1....0...-2....3....3...-2....3....2....0...-2...-1
..3....2...-1....1....0...-2...-3...-3....2...-2....1....2....3....3...-3....0
..0...-1...-2....2...-3....1....0...-2...-1...-3....0...-1...-2...-2....2...-1
..1...-2...-1....3...-2...-2....3....3....2....2....1...-2...-3....3....1....0
.-2...-3....0...-2...-1...-1...-2....2...-3...-3....2....1....0...-2....0...-3
..1....2....3...-3...-2....2....1....3....2...-2...-3...-2...-3...-1...-3....2
..0....3....2....2....3...-1....0...-2...-3....3...-2....1....2....2....2....3
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Cf. A202076.

Formula

Empirical: a(n) = 8*a(n-1) -28*a(n-2) +56*a(n-3) -70*a(n-4) +56*a(n-5) -28*a(n-6) +8*a(n-7) -a(n-8).

Empirical g.f.: 4*x*(1 + x)*(3 + 104*x + 390*x^2 + 104*x^3 + 3*x^4) / (1 - x)^8. - Colin Barker, May 27 2018