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A205342 Number of length 5 nonnegative integer arrays starting and ending with 0 with adjacent elements unequal but differing by no more than n. 1
2, 11, 35, 82, 160, 277, 441, 660, 942, 1295, 1727, 2246, 2860, 3577, 4405, 5352, 6426, 7635, 8987, 10490, 12152, 13981, 15985, 18172, 20550, 23127, 25911, 28910, 32132, 35585, 39277, 43216, 47410, 51867, 56595, 61602, 66896, 72485, 78377, 84580, 91102 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Row 4 of A205341.
LINKS
FORMULA
Empirical: a(n) = (4/3)*n^3 - (1/2)*n^2 + (7/6)*n.
Conjectures from Colin Barker, Jun 11 2018: (Start)
G.f.: x*(2 + 3*x + 3*x^2) / (1 - x)^4.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n>4.
(End)
EXAMPLE
Some solutions for n=5:
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..2....5....3....2....2....1....5....2....5....4....1....5....4....4....5....2
..0....8....6....4....6....6....1....7....1....9....6....7....5....2....8....5
..3....3....5....1....5....2....2....3....5....4....5....4....2....4....5....4
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
CROSSREFS
Cf. A205341.
Sequence in context: A204452 A337640 A041389 * A000914 A256317 A086735
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 26 2012
STATUS
approved

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Last modified June 20 19:12 EDT 2024. Contains 373532 sequences. (Running on oeis4.)