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A246740 Number of length 3+4 0..n arrays with no pair in any consecutive five terms totalling exactly n.

%I A246740 #6 Jul 23 2025 11:32:05
%S A246740 2,22,548,2884,18966,66378,241544,643048,1687850,3716830,7980972,
%T A246740 15368172,28868798,50412754,86141456,139758928,222590034,341128998,
%U A246740 514651700,753789460,1089386342,1537935322,2146429848,2939373624
%N A246740 Number of length 3+4 0..n arrays with no pair in any consecutive five terms totalling exactly n.
%C A246740 Row 3 of A246737
%H A246740 R. H. Hardin, <a href="/A246740/b246740.txt">Table of n, a(n) for n = 1..71</a>
%F A246740 Empirical: a(n) = 3*a(n-1) +2*a(n-2) -14*a(n-3) +5*a(n-4) +25*a(n-5) -20*a(n-6) -20*a(n-7) +25*a(n-8) +5*a(n-9) -14*a(n-10) +2*a(n-11) +3*a(n-12) -a(n-13)
%e A246740 Some solutions for n=4
%e A246740 ..2....4....1....3....2....0....4....3....0....4....0....4....3....3....4....4
%e A246740 ..4....4....2....3....1....3....3....2....3....1....1....1....3....2....1....3
%e A246740 ..4....4....1....3....1....0....3....0....2....1....0....4....3....4....4....4
%e A246740 ..3....1....1....3....1....3....3....0....0....2....2....2....4....4....1....3
%e A246740 ..4....2....1....2....1....3....2....3....3....4....1....1....2....4....2....3
%e A246740 ..3....4....1....0....0....0....3....3....3....1....1....1....3....4....1....2
%e A246740 ..4....1....2....3....1....0....3....3....3....1....1....4....4....2....4....3
%K A246740 nonn
%O A246740 1,1
%A A246740 _R. H. Hardin_, Sep 02 2014