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A193698 Number of arrays of -4..4 integers x(1..n) with every x(i) in a subsequence of length 1, 2 or 3 with sum zero 1
1, 9, 69, 317, 1741, 9385, 50035, 268453, 1438203, 7705011, 41284941, 221198177, 1185157449, 6349965025, 34022467117, 182289038899, 976686732167, 5232991207579, 28037851489661, 150224045883455, 804885636881145 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 4 of A193702
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) -6*a(n-2) +3*a(n-3) +33*a(n-4) +97*a(n-5) +56*a(n-6) +410*a(n-7) +879*a(n-8) +1783*a(n-9) +3145*a(n-10) +7753*a(n-11) +10683*a(n-12) +18787*a(n-13) +28728*a(n-14) +40680*a(n-15) +46937*a(n-16) +53760*a(n-17) +15971*a(n-18) -19648*a(n-19) -105105*a(n-20) -160613*a(n-21) -198846*a(n-22) -149920*a(n-23) -86466*a(n-24) +71880*a(n-25) +113537*a(n-26) +220479*a(n-27) +140242*a(n-28) +136646*a(n-29) +17320*a(n-30) -6999*a(n-31) -64171*a(n-32) -52874*a(n-33) -51993*a(n-34) -26792*a(n-35) -14383*a(n-36) -1773*a(n-37) +1763*a(n-38) +3249*a(n-39) +2387*a(n-40) +1554*a(n-41) +741*a(n-42) +312*a(n-43) +109*a(n-44) +35*a(n-45) +8*a(n-46) +a(n-47)
EXAMPLE
Some solutions for n=6
..0....3....4...-3...-3...-2....2....2....3....3...-3...-1...-4....2....2...-1
..2...-3...-3....2...-1....2...-2...-2...-4...-3....2...-3....2...-2...-2....1
..0....2...-1....1....4...-3....1....1....1....3....1....4....2...-1....0...-2
.-2...-2...-4...-2...-4....1....1...-1....2...-1....0....0...-4....1....2....1
..1....0....4....2....2...-1....4....0...-3...-3....0....0....1...-4...-2...-3
.-1....0...-4...-2....2....1...-4....0....0....4....0....0...-1....3....0....2
CROSSREFS
Sequence in context: A120306 A197425 A089379 * A188800 A297393 A072258
KEYWORD
nonn
AUTHOR
R. H. Hardin Aug 02 2011
STATUS
approved

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Last modified March 29 06:44 EDT 2024. Contains 371265 sequences. (Running on oeis4.)