|
%I #10 Oct 16 2017 09:58:07
%S 161,636,2507,10213,42182,173606,710976,2908797,11911516,48807427,
%T 199987737,819315100,3356387171,13749952752,56330082115,230771042950,
%U 945410224602,3873094298871,15867039092263,65003096433432
%N Number of 0..5 arrays x(0..n+1) of n+2 elements without any interior element greater than both neighbors.
%C Column 5 of A200886.
%H R. H. Hardin, <a href="/A200883/b200883.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 6*a(n-1) -15*a(n-2) +35*a(n-3) -35*a(n-4) +56*a(n-5) -28*a(n-6) +36*a(n-7) -9*a(n-8) +10*a(n-9) -a(n-10) +a(n-11).
%F Empirical g.f.: x*(161 - 330*x + 1106*x^2 - 924*x^3 + 1884*x^4 - 792*x^5 + 1252*x^6 - 264*x^7 + 355*x^8 - 30*x^9 + 36*x^10) / (1 - 6*x + 15*x^2 - 35*x^3 + 35*x^4 - 56*x^5 + 28*x^6 - 36*x^7 + 9*x^8 - 10*x^9 + x^10 - x^11). - _Colin Barker_, Oct 16 2017
%e Some solutions for n=3
%e ..4....3....5....4....3....5....2....2....1....2....4....0....1....2....2....4
%e ..4....4....2....0....5....3....1....4....2....2....1....2....0....4....0....0
%e ..3....4....1....0....5....1....2....4....4....4....1....3....0....4....1....3
%e ..1....0....0....2....5....1....2....1....4....4....1....3....1....4....3....3
%e ..0....2....1....5....3....0....3....4....4....0....2....0....3....1....3....3
%K nonn
%O 1,1
%A _R. H. Hardin_, Nov 23 2011
| 