cp's OEIS Frontend

A268955 Number of length-n 0..7 arrays with no repeated value equal to the previous repeated value, with new values introduced in sequential order.

%I A268955 #4 Feb 16 2016 11:50:38
%S A268955 1,2,4,12,40,154,656,3074,15615,85314,497262,3068890,19899645,
%T A268955 134520386,940841796,6760952170,49617422739,370013347266,
%U A268955 2792665457338,21266237427018,163008076378489,1255477313622210,9703388630792784
%N A268955 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 A268955 Column 7 of A268956.
%H A268955 R. H. Hardin, <a href="/A268955/b268955.txt">Table of n, a(n) for n = 1..210</a>
%F A268955 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 A268955 Some solutions for n=8
%e A268955 ..0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0
%e A268955 ..1. .0. .1. .0. .1. .1. .0. .1. .1. .0. .1. .1. .0. .1. .1. .1
%e A268955 ..2. .1. .2. .1. .2. .1. .1. .0. .2. .1. .2. .2. .1. .0. .2. .0
%e A268955 ..0. .2. .2. .0. .0. .0. .2. .2. .3. .2. .3. .1. .1. .2. .0. .2
%e A268955 ..1. .3. .1. .2. .2. .2. .1. .3. .4. .3. .3. .2. .2. .0. .3. .3
%e A268955 ..2. .4. .0. .1. .1. .3. .3. .0. .5. .2. .4. .3. .0. .1. .2. .0
%e A268955 ..2. .1. .3. .2. .3. .0. .4. .3. .2. .4. .2. .1. .2. .3. .2. .4
%e A268955 ..3. .1. .1. .0. .1. .1. .2. .3. .6. .5. .4. .2. .1. .0. .4. .2
%Y A268955 Cf. A268956.
%K A268955 nonn
%O A268955 1,2
%A A268955 _R. H. Hardin_, Feb 16 2016