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A183900 Number of nondecreasing arrangements of n+3 numbers in 0..5 with each number being the sum mod 6 of three others. 1

%I #8 Apr 05 2018 11:13:05

%S 3,24,130,364,771,1386,2281,3534,5236,7492,10422,14162,18865,24702,

%T 31863,40558,51018,63496,78268,95634,115919,139474,166677,197934,

%U 233680,274380,320530,372658,431325,497126,570691,652686,743814,844816,956472,1079602

%N Number of nondecreasing arrangements of n+3 numbers in 0..5 with each number being the sum mod 6 of three others.

%C Column 5 of A183904.

%H R. H. Hardin, <a href="/A183900/b183900.txt">Table of n, a(n) for n = 1..57</a>

%F Empirical: a(n) = (1/120)*n^5 + (1/4)*n^4 + (71/24)*n^3 + (57/4)*n^2 - (262/15)*n - 50 for n>4.

%F Conjectures from _Colin Barker_, Apr 05 2018: (Start)

%F G.f.: x*(3 + 6*x + 31*x^2 - 116*x^3 + 102*x^4 - 38*x^5 + 59*x^6 - 78*x^7 + 38*x^8 - 6*x^9) / (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>10.

%F (End)

%e Some solutions for n=2:

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

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

%e ..4....5....2....3....2....2....0....1....4....2....4....5....3....3....2....1

%e ..4....5....4....4....2....2....0....2....5....3....4....5....5....3....2....3

%e ..4....5....4....5....4....2....0....4....5....4....4....5....5....3....4....3

%Y Cf. A183904.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 07 2011

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Last modified April 19 11:14 EDT 2024. Contains 371791 sequences. (Running on oeis4.)