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A188185 Number of strictly increasing arrangements of 7 numbers in -(n+5)..(n+5) with sum zero 4
94, 289, 734, 1656, 3370, 6375, 11322, 19138, 30982, 48417, 73316, 108108, 155646, 219489, 303748, 413442, 554256, 733005, 957332, 1236222, 1579666, 1999265, 2507780, 3119876, 3851588, 4721127, 5748298, 6955424, 8366614, 10008857 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 7 of A188181

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.  -x*(94 +101*x +156*x^2 +282*x^3 +347*x^4 +463*x^5 +423*x^6 +497*x^7 +393*x^8 +285*x^9 +180*x^10 +99*x^11 +17*x^12 -25*x^13 +47*x^14 -19*x^15 +25*x^16 +4*x^17 +22*x^18 -7*x^19 -44*x^20 +24*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 26 2011

EXAMPLE

Some solutions for n=5

.-9...-7...-9..-10..-10..-10...-7...-9..-10..-10..-10..-10..-10...-9...-7..-10

.-7...-4...-7...-6...-7...-4...-6...-7...-3...-8...-5...-8...-8...-6...-6...-6

.-3...-2...-2...-5...-3...-3...-4...-4...-1...-2...-1...-7...-5...-1...-3...-5

.-1...-1....0....2....2...-1...-3....1....0...-1....1....3...-1....1...-2....1

..5....0....3....4....3....3....4....2....1....5....2....6....6....2....0....4

..6....6....6....7....6....7....7....8....4....7....4....7....8....4....8....7

..9....8....9....8....9....8....9....9....9....9....9....9...10....9...10....9

CROSSREFS

Sequence in context: A116109 A107412 A115996 * A189811 A202415 A174337

Adjacent sequences:  A188182 A188183 A188184 * A188186 A188187 A188188

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 23 2011

STATUS

approved

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Last modified June 22 07:47 EDT 2017. Contains 288605 sequences.