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A246891 Number of length n+4 0..7 arrays with some pair in every consecutive five terms totalling exactly 7.

%I A246891 #6 Jun 02 2025 10:14:46
%S A246891 23400,159688,1079680,7216512,47799488,319477960,2132283592,
%T A246891 14219886016,94826520320,632600369216,4219646774184,28145459043464,
%U A246891 187735748042496,1252250358585088,8352796888611456,55715038868965512,371632331032444552
%N A246891 Number of length n+4 0..7 arrays with some pair in every consecutive five terms totalling exactly 7.
%C A246891 Column 7 of A246892
%H A246891 R. H. Hardin, <a href="/A246891/b246891.txt">Table of n, a(n) for n = 1..210</a>
%F A246891 Empirical: a(n) = 4*a(n-1) +10*a(n-2) +38*a(n-3) +132*a(n-4) -233*a(n-5) -124*a(n-6) -48*a(n-7) -152*a(n-8) +232*a(n-9) +97*a(n-10) -80*a(n-11) +14*a(n-12) -6*a(n-13) -4*a(n-14) +a(n-15)
%e A246891 Some solutions for n=2
%e A246891 ..4....0....0....4....1....5....6....1....5....6....2....4....2....2....4....4
%e A246891 ..7....3....7....7....2....2....4....6....6....3....2....5....2....7....7....1
%e A246891 ..6....6....3....3....7....3....1....1....2....5....1....3....5....3....3....1
%e A246891 ..0....4....5....0....6....3....7....6....7....5....3....1....1....4....5....0
%e A246891 ..7....7....0....4....1....4....6....1....0....2....6....6....1....6....4....7
%e A246891 ..5....7....4....4....2....6....4....1....7....1....0....6....1....3....6....2
%K A246891 nonn
%O A246891 1,1
%A A246891 _R. H. Hardin_, Sep 06 2014