A249706 - OEIS

A249706

Number of length n+3 0..7 arrays with every four consecutive terms having the maximum of some two terms equal to the minimum of the remaining two terms.

%I #6 Jan 01 2024 02:08:04

%S 904,2864,8688,24032,57912,156416,442144,1235840,3295784,8902160,

%T 24576568,68205968,186882480,511124496,1407327072,3893357456,

%U 10747255576,29617387520,81753189024,226221330256,626221254528,1732751390816

%N Number of length n+3 0..7 arrays with every four consecutive terms having the maximum of some two terms equal to the minimum of the remaining two terms.

%C Column 7 of A249707.

%H R. H. Hardin, <a href="/A249706/b249706.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) -6*a(n-2) +4*a(n-3) +111*a(n-4) -308*a(n-5) +280*a(n-6) -84*a(n-7) -5194*a(n-8) +8288*a(n-9) -3066*a(n-10) +130820*a(n-12) -74128*a(n-13) -10560*a(n-14) -8848*a(n-15) -2004617*a(n-16) -633508*a(n-17) -130504*a(n-18) +130916*a(n-19) +20088708*a(n-20) +21173952*a(n-21) +13092164*a(n-22) +5552064*a(n-23) -132853024*a(n-24) -224564176*a(n-25) -190931472*a(n-26) -114274368*a(n-27) +557555040*a(n-28) +1305213120*a(n-29) +1329331968*a(n-30) +881028864*a(n-31) -1386528192*a(n-32) -4476415104*a(n-33) -5034923712*a(n-34) -3297853440*a(n-35) +1793560320*a(n-36) +8714615040*a(n-37) +10059033600*a(n-38) +5654707200*a(n-39) -1157068800*a(n-40) -7838208000*a(n-41) -7838208000*a(n-42) -2612736000*a(n-43).

%e Some solutions for n=6

%e ..4....2....6....1....4....4....1....0....2....2....4....2....4....4....6....4

%e ..3....0....3....7....4....3....2....1....6....0....1....0....3....3....3....6

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

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

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

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

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

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

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

%Y Cf. A249707.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 04 2014