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A188186 Number of strictly increasing arrangements of 8 numbers in -(n+6)..(n+6) with sum zero 1
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 (list; graph; refs; listen; history; text; internal format)
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 A156575

Adjacent sequences:  A188183 A188184 A188185 * A188187 A188188 A188189

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 23 2011

STATUS

approved

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Last modified March 30 04:55 EDT 2017. Contains 284296 sequences.