A254691 - OEIS

%I #9 Dec 17 2018 09:12:55

%S 22,34,54,86,136,212,334,532,852,1367,2193,3522,5669,9143,14763,23854,

%T 38564,62381,100966,163491,264822,429064,695313,1126988,1826949,

%U 2962017,4802762,7788052,12629762,20482614,33219658,53879144,87389439,141744960

%N Number of length n+4 0..1 arrays with every five consecutive terms having the maximum of some two terms equal to the minimum of the remaining three terms.

%H R. H. Hardin, <a href="/A254691/b254691.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) - a(n-2) + a(n-3) - a(n-4) + 3*a(n-5) - 3*a(n-6) - 2*a(n-8) + a(n-9) - 3*a(n-10) + a(n-11) + a(n-13) + a(n-15).

%F Empirical g.f.: x*(22 - 10*x + 8*x^2 - 10*x^3 + 6*x^4 - 60*x^5 - 22*x^6 - 34*x^7 - 6*x^8 - 31*x^9 + 25*x^10 + 15*x^11 + 23*x^12 + 11*x^13 + 16*x^14) / ((1 - x + x^2)*(1 - x^2 - x^3)*(1 - x - x^3 - 2*x^5 + x^8 + x^10)). - _Colin Barker_, Dec 17 2018

%e Some solutions for n=10:

%e ..0....1....0....0....0....0....1....1....0....0....1....0....1....0....1....0

%e ..0....0....0....1....0....0....0....0....1....0....0....1....0....0....0....0

%e ..1....1....0....0....0....1....0....0....1....0....0....0....0....0....0....1

%e ..0....1....0....0....0....0....0....0....0....1....1....0....1....1....1....1

%e ..0....1....0....0....0....0....0....0....0....0....0....1....0....0....0....0

%e ..0....1....0....0....0....0....0....1....0....0....0....0....0....1....0....0

%e ..0....1....1....0....0....1....0....1....0....0....0....0....1....0....0....0

%e ..0....1....0....0....0....0....0....0....1....0....1....0....0....0....0....1

%e ..0....1....0....1....1....0....1....0....0....0....1....0....0....1....0....0

%e ..0....1....0....0....0....0....0....0....0....0....0....1....0....0....0....1

%e ..0....1....0....0....1....0....0....1....1....0....0....0....0....0....0....0

%e ..1....1....1....1....0....1....1....1....0....0....0....0....1....0....0....0

%e ..1....1....0....0....0....0....0....0....0....1....1....0....1....1....1....1

%e ..0....0....0....1....0....0....1....0....0....1....1....0....0....0....1....0

%Y Column 1 of A254698.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 05 2015