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A241966 Number of length 3+3 0..n arrays with no consecutive four elements summing to more than 2*n. 1

%I #8 Oct 31 2018 06:33:43

%S 33,311,1597,5778,16660,40978,89622,179079,333091,584529,977483,

%T 1569568,2434446,3664564,5374108,7702173,10816149,14915323,20234697,

%U 27049022,35677048,46485990,59896210,76386115,96497271,120839733,150097591

%N Number of length 3+3 0..n arrays with no consecutive four elements summing to more than 2*n.

%H R. H. Hardin, <a href="/A241966/b241966.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = (3/10)*n^6 + (127/60)*n^5 + (149/24)*n^4 + (59/6)*n^3 + (1079/120)*n^2 + (91/20)*n + 1.

%F Conjectures from _Colin Barker_, Oct 31 2018: (Start)

%F G.f.: x*(33 + 80*x + 113*x^2 - 25*x^3 + 21*x^4 - 7*x^5 + x^6) / (1 - x)^7.

%F a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.

%F (End)

%e Some solutions for n=4:

%e ..4....1....0....3....2....1....4....1....1....2....3....0....4....3....2....0

%e ..3....0....4....4....0....1....0....4....0....4....2....4....3....1....0....3

%e ..1....0....0....0....0....1....0....1....0....0....2....0....1....3....2....4

%e ..0....1....0....1....3....0....0....0....2....0....1....3....0....1....0....1

%e ..4....4....0....3....1....3....1....3....3....0....0....0....3....1....4....0

%e ..1....2....0....3....1....0....0....2....2....4....2....3....2....0....1....3

%Y Row 3 of A241964.

%K nonn

%O 1,1

%A _R. H. Hardin_, May 03 2014

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Last modified April 25 16:23 EDT 2024. Contains 371989 sequences. (Running on oeis4.)