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A246899 Number of length 7+4 0..n arrays with some pair in every consecutive five terms totalling exactly n.

%I A246899 #6 Jul 23 2025 11:33:10
%S A246899 1546,140893,2390116,25710385,139555230,647845357,2132283592,
%T A246899 6483573889,16272395890,38904095581,82432596396,168949326193,
%U A246899 318823302406,587124413485,1018357762960,1733359959937,2819557291482,4517952689629
%N A246899 Number of length 7+4 0..n arrays with some pair in every consecutive five terms totalling exactly n.
%C A246899 Row 7 of A246892
%H A246899 R. H. Hardin, <a href="/A246899/b246899.txt">Table of n, a(n) for n = 1..59</a>
%F A246899 Empirical: a(n) = 2*a(n-1) +7*a(n-2) -16*a(n-3) -20*a(n-4) +56*a(n-5) +28*a(n-6) -112*a(n-7) -14*a(n-8) +140*a(n-9) -14*a(n-10) -112*a(n-11) +28*a(n-12) +56*a(n-13) -20*a(n-14) -16*a(n-15) +7*a(n-16) +2*a(n-17) -a(n-18)
%e A246899 Some solutions for n=2
%e A246899 ..1....0....0....0....0....0....1....0....1....0....1....2....0....1....0....2
%e A246899 ..0....1....0....1....0....2....2....2....2....1....2....0....0....0....1....0
%e A246899 ..2....0....2....2....1....2....1....0....1....2....0....0....2....1....1....0
%e A246899 ..2....1....2....2....0....2....0....0....1....0....1....0....1....1....0....2
%e A246899 ..2....1....0....1....2....0....2....2....1....1....1....2....0....2....1....0
%e A246899 ..2....0....1....1....0....0....1....1....1....2....2....1....1....0....0....1
%e A246899 ..0....2....2....2....0....2....2....1....0....0....2....2....0....0....1....1
%e A246899 ..2....2....0....1....1....0....0....0....0....1....1....0....2....1....2....2
%e A246899 ..1....2....1....2....2....0....1....1....1....0....1....0....0....0....1....1
%e A246899 ..0....0....1....0....0....2....1....0....1....2....0....1....2....1....1....2
%e A246899 ..0....0....1....0....2....1....1....2....0....0....2....1....1....2....1....2
%K A246899 nonn
%O A246899 1,1
%A A246899 _R. H. Hardin_, Sep 06 2014