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 A208966 Number of n-bead necklaces labeled with numbers -4..4 allowing reversal, with sum zero and first and second differences in -4..4. 1

%I

%S 1,2,2,8,19,90,371,1755,8092,37970,179133,857902,4152036,20313811,

%T 100217735,497983883,2488970462,12503041095,63083893996,319545209584,

%U 1624399382535,8284482761844,42377064630483,217362286106711,1117715413419540,5760869940768290

%N Number of n-bead necklaces labeled with numbers -4..4 allowing reversal, with sum zero and first and second differences in -4..4.

%H Andrew Howroyd, <a href="/A208966/b208966.txt">Table of n, a(n) for n = 1..50</a>

%e Some solutions for n=5:

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

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

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

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

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

%Y Column 4 of A208970.

%K nonn

%O 1,2

%A _R. H. Hardin_, Mar 03 2012

%E a(16)-a(26) from _Andrew Howroyd_, Mar 12 2017

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Last modified December 7 22:29 EST 2019. Contains 329850 sequences. (Running on oeis4.)