A268955 - OEIS

%I #4 Feb 16 2016 11:50:38

%S 1,2,4,12,40,154,656,3074,15615,85314,497262,3068890,19899645,

%T 134520386,940841796,6760952170,49617422739,370013347266,

%U 2792665457338,21266237427018,163008076378489,1255477313622210,9703388630792784

%N Number of length-n 0..7 arrays with no repeated value equal to the previous repeated value, with new values introduced in sequential order.

%C Column 7 of A268956.

%H R. H. Hardin, <a href="/A268955/b268955.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 38*a(n-1) -593*a(n-2) +4702*a(n-3) -17263*a(n-4) -4158*a(n-5) +265149*a(n-6) -681270*a(n-7) -916836*a(n-8) +6212496*a(n-9) -2473032*a(n-10) -24948000*a(n-11) +25941088*a(n-12) +53418784*a(n-13) -73975984*a(n-14) -60452512*a(n-15) +93916672*a(n-16) +28869120*a(n-17) -45158400*a(n-18) for n>20

%e Some solutions for n=8

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

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

%e ..2. .1. .2. .1. .2. .1. .1. .0. .2. .1. .2. .2. .1. .0. .2. .0

%e ..0. .2. .2. .0. .0. .0. .2. .2. .3. .2. .3. .1. .1. .2. .0. .2

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

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

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

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

%Y Cf. A268956.

%K nonn

%O 1,2

%A _R. H. Hardin_, Feb 16 2016