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A252179 Number of length 3+2 0..n arrays with the sum of the maximum minus the minimum of adjacent triples multiplied by some arrangement of +-1 equal to zero. 1
12, 83, 264, 687, 1428, 2729, 4680, 7661, 11764, 17535, 25056, 35067, 47628, 63701, 83312, 107673, 136764, 172075, 213528, 262919, 320100, 387201, 463992, 552965, 653796, 769367, 899248, 1046739, 1211292, 1396653, 1602144, 1831985, 2085356 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 3*a(n-1) - 8*a(n-3) + 6*a(n-4) + 6*a(n-5) - 8*a(n-6) + 3*a(n-8) - a(n-9).

Empirical for n mod 2 = 0: a(n) = (1/60)*n^5 + (17/16)*n^4 + (14/3)*n^3 + (11/2)*n^2 + (77/30)*n + 1.

Empirical for n mod 2 = 1: a(n) = (1/60)*n^5 + (17/16)*n^4 + (14/3)*n^3 + (39/8)*n^2 + (79/60)*n + (1/16).

Empirical g.f.: x*(12 + 47*x + 15*x^2 - 9*x^3 - 41*x^4 - 13*x^5 + 3*x^6 + 3*x^7 - x^8) / ((1 - x)^6*(1 + x)^3). - Colin Barker, Dec 01 2018

EXAMPLE

Some solutions for n=6:

..6....6....2....5....5....6....0....2....5....0....0....4....4....4....0....2

..0....0....0....5....5....1....3....1....3....1....1....4....5....0....3....1

..4....0....3....3....5....2....3....1....6....1....1....6....6....1....2....5

..4....2....0....0....0....0....4....5....6....1....2....6....3....2....2....6

..2....4....6....3....3....3....0....0....0....0....3....2....1....3....4....5

CROSSREFS

Row 3 of A252177.

Sequence in context: A239180 A290715 A175037 * A102105 A275743 A026949

Adjacent sequences:  A252176 A252177 A252178 * A252180 A252181 A252182

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 15 2014

STATUS

approved

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Last modified February 16 21:59 EST 2019. Contains 320200 sequences. (Running on oeis4.)