A188337 Number of nondecreasing arrangements of 7 nonzero numbers in -(n+5)..(n+5) with sum zero

980, 2128, 4238, 7836, 13694, 22786, 36454, 56314, 84496, 123512, 176534, 247236, 340148, 460412, 614240, 808614, 1051792, 1352972, 1722892, 2173378, 2718084, 3371956, 4152034, 5076868, 6167438, 7446422, 8939282, 10673432, 12679398

Offset

1,1

Comments

Row 7 of A188333

Links

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

Formula

Empirical: a(n)=2*a(n-1)-a(n-3)-a(n-5)+a(n-6)-2*a(n-7)+2*a(n-8)+a(n-9)-a(n-13)-2*a(n-14)+2*a(n-15)-a(n-16)+a(n-17)+a(n-19)-2*a(n-21)+a(n-22).

Empirical: G.f. -2*x*(490 +84*x -9*x^2 +170*x^3 +75*x^4 +308*x^5 -67*x^6 +585*x^7 +274*x^8 +36*x^9 -8*x^10 -95*x^11 -302*x^12 -273*x^13 +345*x^14 -126*x^15 +216*x^16 +63*x^17 +165*x^18 -120*x^19 -327*x^20 +198*x^21) / ( (x^2-x+1) *(x^4+x^3+x^2+x+1) *(x^2+1) *(1+x+x^2)^2 *(1+x)^3 *(x-1)^7 ). - R. J. Mathar, Mar 28 2011

Example

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

Crossrefs

Sequence in context: A108904 A091080 A157515 * A109120 A128483 A056937

Adjacent sequences: A188334 A188335 A188336 * A188338 A188339 A188340

Keyword

nonn

Author

R. H. Hardin Mar 28 2011

Status

approved