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A208801 Number of n-bead necklaces labeled with numbers -4..4 allowing reversal, with sum zero and three times sum of squares <= n*(4)*(4+1). 1

%I #12 Mar 12 2017 22:48:53

%S 1,3,8,50,239,1746,11557,82577,648289,4806475,36522073,300186549,

%T 2339239465,18355175927,154771130241,1236373902645,9941856371385,

%U 85100077549321,691573737441489,5648994401150475

%N Number of n-bead necklaces labeled with numbers -4..4 allowing reversal, with sum zero and three times sum of squares <= n*(4)*(4+1).

%C Column 4 of A208805.

%H Andrew Howroyd, <a href="/A208801/b208801.txt">Table of n, a(n) for n = 1..50</a>

%e Some solutions for n=6:

%e .-3...-4...-4...-3...-2...-2...-3...-2...-3...-4...-3...-3...-4...-3...-4...-3

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

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

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

%e ..2....1....2...-2....3...-2....4....2....2....2....4....1....3...-2....1....1

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

%K nonn

%O 1,2

%A _R. H. Hardin_, Mar 01 2012

%E a(15)-a(20) from _Andrew Howroyd_, Mar 02 2017

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Last modified March 29 02:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)