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A199848 Number of -n..n arrays x(0..3) of 4 elements with zero sum and no element more than one greater than the previous. 1
11, 23, 42, 68, 103, 149, 206, 276, 361, 461, 578, 714, 869, 1045, 1244, 1466, 1713, 1987, 2288, 2618, 2979, 3371, 3796, 4256, 4751, 5283, 5854, 6464, 7115, 7809, 8546, 9328, 10157, 11033, 11958, 12934, 13961, 15041, 16176, 17366, 18613, 19919, 21284 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 4 of A199847.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 3*a(n-1) -3*a(n-2) +2*a(n-3) -3*a(n-4) +3*a(n-5) -a(n-6).

Empirical g.f.: x*(11 - 10*x + 6*x^2 - 11*x^3 + 12*x^4 - 4*x^5) / ((1 - x)^4*(1 + x + x^2)). - Colin Barker, May 16 2018

EXAMPLE

Some solutions for n=6:

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

..1....1....2...-1....5....2....2....3...-1....1....1....2....1....1....2....3

.-2....2...-1...-2...-5....2...-2...-3...-1...-1....1....1...-3....1...-2...-3

.-2...-5...-5...-2...-4...-5...-6...-6...-3...-6...-5...-4...-3...-4...-3...-3

CROSSREFS

Cf. A199847.

Sequence in context: A077041 A190797 A068842 * A228444 A191235 A146451

Adjacent sequences:  A199845 A199846 A199847 * A199849 A199850 A199851

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 11 2011

STATUS

approved

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Last modified February 25 11:16 EST 2021. Contains 341606 sequences. (Running on oeis4.)