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 A222890 Number of n X 1 0..7 arrays with no element equal to another at a city block distance of exactly two, and new values 0..7 introduced in row major order. 1

%I #9 Aug 16 2018 13:22:52

%S 1,2,3,7,20,67,255,1080,5016,25249,136289,780658,4696002,29374011,

%T 189373083,1248978556,8376922028,56874440053,389553674037,

%U 2685020105574,18589701176694,129115803986575,898809701733551,6266899328414512

%N Number of n X 1 0..7 arrays with no element equal to another at a city block distance of exactly two, and new values 0..7 introduced in row major order.

%C Column 1 of A222894.

%H R. H. Hardin, <a href="/A222890/b222890.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 22*a(n-1) - 190*a(n-2) + 820*a(n-3) - 1849*a(n-4) + 2038*a(n-5) - 840*a(n-6) for n>8.

%F Empirical g.f.: x*(1 + x)*(1 - 21*x + 170*x^2 - 669*x^3 + 1314*x^4 - 1157*x^5 + 309*x^6) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)*(1 - 7*x)). - _Colin Barker_, Aug 16 2018

%e All solutions for n=3:

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

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

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

%Y Cf. A222894.

%K nonn

%O 1,2

%A _R. H. Hardin_, Mar 08 2013

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Last modified November 29 00:31 EST 2023. Contains 367422 sequences. (Running on oeis4.)