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A200885 Number of 0..7 arrays x(0..n+1) of n+2 elements without any interior element greater than both neighbors. 1
372, 1856, 9052, 45648, 235538, 1215616, 6233356, 31868448, 163014678, 834763824, 4276077566, 21900661172, 112149148911, 574278200480, 2940790043388, 15059692639376, 77120252989206, 394927990211792, 2022395235481866 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 7 of A200886.

LINKS

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

FORMULA

Empirical: a(n) = 8*a(n-1) -28*a(n-2) +84*a(n-3) -126*a(n-4) +252*a(n-5) -210*a(n-6) +330*a(n-7) -165*a(n-8) +220*a(n-9) -66*a(n-10) +78*a(n-11) -13*a(n-12) +14*a(n-13) -a(n-14) +a(n-15).

Empirical g.f.: x*(372 - 1120*x + 4620*x^2 - 6048*x^3 + 14778*x^4 - 10800*x^5 + 20020*x^6 - 8800*x^7 + 13630*x^8 - 3600*x^9 + 4902*x^10 - 720*x^11 + 889*x^12 - 56*x^13 + 64*x^14) / (1 - 8*x + 28*x^2 - 84*x^3 + 126*x^4 - 252*x^5 + 210*x^6 - 330*x^7 + 165*x^8 - 220*x^9 + 66*x^10 - 78*x^11 + 13*x^12 - 14*x^13 + x^14 - x^15). - Colin Barker, Oct 16 2017

EXAMPLE

Some solutions for n=3

..7....6....6....6....4....2....6....7....7....2....5....3....5....6....0....3

..6....4....5....6....1....1....6....6....6....3....6....0....4....0....2....7

..3....5....3....0....1....1....2....3....6....3....6....4....3....2....4....7

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

..7....6....4....6....5....7....6....1....6....6....4....7....3....4....6....1

CROSSREFS

Sequence in context: A203924 A004021 A240249 * A161361 A265659 A238774

Adjacent sequences:  A200882 A200883 A200884 * A200886 A200887 A200888

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 23 2011

STATUS

approved

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Last modified June 28 11:24 EDT 2022. Contains 354905 sequences. (Running on oeis4.)