A188186 Number of strictly increasing arrangements of 8 numbers in -(n+6)..(n+6) with sum zero

289, 910, 2430, 5744, 12346, 24591, 46029, 81805, 139143, 227930, 361384, 556834, 836618, 1229093, 1769773, 2502617, 3481445, 4771508, 6451232, 8614108, 11370764, 14851235, 19207395, 24615603, 31279561, 39433366, 49344790, 61318804, 75701312

Offset

1,1

Comments

Row 8 of A188181

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=3*a(n-1)-2*a(n-2)-3*a(n-4)+4*a(n-5)-3*a(n-8)+3*a(n-9)-a(n-11)-a(n-12)+3*a(n-14)-3*a(n-15)+4*a(n-18)-3*a(n-19)-2*a(n-21)+3*a(n-22)-a(n-23).

Empirical: G.f. -x*(-289 -43*x -278*x^2 -274*x^3 -841*x^4 -615*x^5 -598*x^6 -412*x^7 -715*x^8 -363*x^9 -163*x^10 -72*x^11 -98*x^12 -200*x^13 +217*x^14 -5*x^15 -49*x^16 -253*x^17 +221*x^18 +23*x^19 +108*x^20 -206*x^21 +73*x^22) / ( (1+x) *(x^4+x^3+x^2+x+1) *(x^6+x^5+x^4+x^3+x^2+x+1) *(1+x+x^2)^2 *(x-1)^8 ). - R. J. Mathar, Mar 26 2011

Example

Some solutions for n=5
.-9..-10..-10...-8..-11...-8...-9..-11...-9..-11..-11...-9..-11..-10..-10...-9
.-8...-8...-9...-7...-3...-5...-8..-10...-8...-7...-5...-7...-4...-9...-9...-7
.-5...-4...-7...-6...-2...-4...-5...-2...-6...-6...-4...-5...-3...-7...-7...-4
.-1....1....0...-2...-1...-3...-4....1...-1...-3...-3...-2...-2...-1....0...-1
..1....2....2....0....1....0...-2....2....3....2....0....0....2....4....4....0
..3....5....6....5....3....5....7....3....4....6....4....3....5....5....5....2
..9....6....8....7....5....6...10....6....7....9....8....9....6....7....6....9
.10....8...10...11....8....9...11...11...10...10...11...11....7...11...11...10

Crossrefs

Sequence in context: A157990 A261111 A218766 * A112077 A152934 A332737

Adjacent sequences: A188183 A188184 A188185 * A188187 A188188 A188189

Keyword

nonn

Author

R. H. Hardin Mar 23 2011

Status

approved