cp's OEIS Frontend

A218646 Number of nX3 arrays of the minimum value of corresponding elements and their horizontal, vertical or antidiagonal neighbors in a random 0..3 nX3 array.

%I A218646 #6 Jul 23 2025 00:02:21
%S A218646 16,66,610,4946,44712,391888,3441914,30316230,266671334,2346850058,
%T A218646 20652411898,181738545458,1599310922692,14073950030962,
%U A218646 123851052268298,1089892156540672,9591074382276762,84401670396996900,742736585615588566
%N A218646 Number of nX3 arrays of the minimum value of corresponding elements and their horizontal, vertical or antidiagonal neighbors in a random 0..3 nX3 array.
%C A218646 Column 3 of A218651
%H A218646 R. H. Hardin, <a href="/A218646/b218646.txt">Table of n, a(n) for n = 1..210</a>
%F A218646 Empirical: a(n) = 8*a(n-1) +6*a(n-2) +27*a(n-3) -123*a(n-4) -58*a(n-5) -2059*a(n-6) -689*a(n-7) +846*a(n-8) -1326*a(n-9) +10232*a(n-10) +28870*a(n-11) -23223*a(n-12) -76249*a(n-13) +22843*a(n-14) +95384*a(n-15) -10406*a(n-16) -67533*a(n-17) -2090*a(n-18) +30314*a(n-19) +3123*a(n-20) -7834*a(n-21) -1293*a(n-22) +1062*a(n-23) +240*a(n-24) -56*a(n-25) -15*a(n-26) for n>27
%e A218646 Some solutions for n=3
%e A218646 ..3..1..1....0..0..0....3..2..2....0..0..3....3..0..0....0..0..1....3..0..0
%e A218646 ..2..1..0....0..0..2....3..2..2....0..0..2....0..0..0....0..1..1....3..0..0
%e A218646 ..1..0..0....1..2..3....3..2..2....0..0..2....0..0..0....2..1..1....2..0..0
%K A218646 nonn
%O A218646 1,1
%A A218646 _R. H. Hardin_ Nov 03 2012