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A250363 Number of length 5 arrays x(i), i=1..5 with x(i) in i..i+n and no value appearing more than 3 times. 1

%I #7 Nov 13 2018 12:48:29

%S 32,243,1016,3094,7712,16700,32608,58826,99704,160672,248360,370718,

%T 537136,758564,1047632,1418770,1888328,2474696,3198424,4082342,

%U 5151680,6434188,7960256,9763034,11878552,14345840,17207048,20507566,24296144

%N Number of length 5 arrays x(i), i=1..5 with x(i) in i..i+n and no value appearing more than 3 times.

%H R. H. Hardin, <a href="/A250363/b250363.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = n^5 + 5*n^4 + 10*n^3 + 5*n^2 + 17*n + 2 for n>2.

%F Conjectures from _Colin Barker_, Nov 13 2018: (Start)

%F G.f.: x*(32 + 51*x + 38*x^2 + 3*x^3 + 8*x^4 - 29*x^5 + 22*x^6 - 5*x^7) / (1 - x)^6.

%F a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>8.

%F (End)

%e Some solutions for n=6:

%e ..1....2....1....2....5....3....5....4....4....3....3....6....2....2....1....3

%e ..3....2....7....4....6....5....5....3....1....1....5....2....7....5....1....7

%e ..6....2....6....5....8....2....4....3....5....7....6....5....8....6....3....4

%e ..4....3....4....8....8....5....6....9....7....4....6....8....4....5....9....9

%e ..4....7....9....4...10...10...10....9....4...10....4...10....9....4...10...10

%Y Row 5 of A250361.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 19 2014

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Last modified April 17 22:23 EDT 2024. Contains 371767 sequences. (Running on oeis4.)