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A200884 Number of 0..6 arrays x(0..n+1) of n+2 elements without any interior element greater than both neighbors. 1
252, 1127, 4977, 22736, 105813, 491533, 2269938, 10462235, 48259083, 222798408, 1028746629, 4749274209, 21922813539, 101196577809, 467142348798, 2156444661242, 9954648966159, 45952741121083, 212127214776309 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 6 of A200886.

LINKS

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

FORMULA

Empirical: a(n) = 7*a(n-1) -21*a(n-2) +56*a(n-3) -70*a(n-4) +126*a(n-5) -84*a(n-6) +120*a(n-7) -45*a(n-8) +55*a(n-9) -11*a(n-10) +12*a(n-11) -a(n-12) +a(n-13).

Empirical g.f.: x*(252 - 637*x + 2380*x^2 - 2548*x^3 + 5706*x^4 - 3276*x^5 + 5620*x^6 - 1820*x^7 + 2630*x^8 - 455*x^9 + 582*x^10 - 42*x^11 + 49*x^12) / (1 - 7*x + 21*x^2 - 56*x^3 + 70*x^4 - 126*x^5 + 84*x^6 - 120*x^7 + 45*x^8 - 55*x^9 + 11*x^10 - 12*x^11 + x^12 - x^13). - Colin Barker, Oct 16 2017

EXAMPLE

Some solutions for n=3

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

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

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

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

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

CROSSREFS

Sequence in context: A046379 A250794 A245858 * A275316 A275315 A184505

Adjacent sequences:  A200881 A200882 A200883 * A200885 A200886 A200887

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 23 2011

STATUS

approved

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Last modified August 18 14:22 EDT 2022. Contains 356215 sequences. (Running on oeis4.)