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A199945 Number of -n..n arrays x(0..3) of 4 elements with zeroth through 3rd differences all nonzero. 1
2, 104, 660, 2474, 6604, 14696, 28490, 50448, 83092, 129642, 193292, 278240, 388258, 528328, 703140, 918330, 1179228, 1492584, 1864202, 2301584, 2811588, 3402266, 4081084, 4857344, 5738882, 6735720, 7856884, 9112842, 10513196, 12069800 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 4 of A199943.

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) +2*a(n-2) -3*a(n-4) -3*a(n-5) +3*a(n-6) +3*a(n-7) -2*a(n-9) -a(n-10) +a(n-11).

Empirical g.f.: 2*x*(1 + 51*x + 276*x^2 + 803*x^3 + 1408*x^4 + 1731*x^5 + 1436*x^6 + 825*x^7 + 303*x^8 + 78*x^9) / ((1 - x)^5*(1 + x)^2*(1 + x + x^2)^2). - Colin Barker, May 17 2018

EXAMPLE

Some solutions for n=6:

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

..1....1...-3...-5....3...-5...-3....5...-6...-6...-2...-5...-3...-1....6...-6

.-5....6....1...-2...-6...-4...-5....2....1...-5....5....1...-2...-4...-6...-5

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

CROSSREFS

Cf. A199943.

Sequence in context: A246775 A281053 A101530 * A265655 A001184 A098653

Adjacent sequences:  A199942 A199943 A199944 * A199946 A199947 A199948

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 12 2011

STATUS

approved

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Last modified May 13 02:02 EDT 2021. Contains 343836 sequences. (Running on oeis4.)