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A188337 Number of nondecreasing arrangements of 7 nonzero numbers in -(n+5)..(n+5) with sum zero 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 24 17:40 EDT 2017. Contains 286997 sequences.