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T(n,k) = number of n-bead necklaces labeled with numbers -k..k not allowing reversal, with sum zero with no three beads in a row equal.
13

%I #7 Mar 12 2017 23:25:49

%S 1,1,2,1,3,2,1,4,6,5,1,5,12,22,8,1,6,20,57,68,20,1,7,30,122,274,264,

%T 38,1,8,42,223,766,1464,988,88,1,9,56,366,1722,5238,7974,3954,196,1,

%U 10,72,563,3376,14430,37044,45050,15980,464,1,11,90,820,6004,33468,125322,270832

%N T(n,k) = number of n-bead necklaces labeled with numbers -k..k not allowing reversal, with sum zero with no three beads in a row equal.

%C Table starts

%C ..1....1.....1......1.......1.......1........1........1........1.........1

%C ..2....3.....4......5.......6.......7........8........9.......10........11

%C ..2....6....12.....20......30......42.......56.......72.......90.......110

%C ..5...22....57....122.....223.....366......563......820.....1143......1544

%C ..8...68...274....766....1722....3376.....6004.....9928....15514.....23178

%C .20..264..1464...5238...14430...33468....68722...128844...225126....371858

%C .38..988..7974..37044..125322..344456...817362..1738516..3397474...6205668

%C .88.3954.45050.270832.1123612.3656654.10024344.24184890.52854218.106749960

%H R. H. Hardin, <a href="/A208945/b208945.txt">Table of n, a(n) for n = 1..182</a>

%e Some solutions for n=5, k=5:

%e .-2...-5...-4...-3...-4...-4...-5...-5...-4...-3...-3...-5...-5...-5...-5...-4

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

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

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

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

%Y Row 3 is A002378.

%K nonn,tabl

%O 1,3

%A _R. H. Hardin_, Mar 03 2012