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A208949 Number of 7-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero with no three beads in a row equal. 1
38, 988, 7974, 37044, 125322, 344456, 817362, 1738516, 3397474, 6205668, 10726862, 17710724, 28129694, 43219580, 64523202, 93937312, 133763354, 186761160, 256205942, 345949192, 460482450, 605004348, 785491674, 1008773192, 1282606758 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 7 of A208945.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 5*a(n-1) - 10*a(n-2) + 11*a(n-3) - 10*a(n-4) + 11*a(n-5) - 9*a(n-6) + 9*a(n-8) - 11*a(n-9) + 10*a(n-10) - 11*a(n-11) + 10*a(n-12) - 5*a(n-13) + a(n-14).

EXAMPLE

Some solutions for n=5:

  -4  -5  -5  -3  -5  -5  -4  -5  -4  -5  -2  -5  -5  -3  -5  -5

   0  -3   3  -2   4   3  -3   2  -2  -2   0  -1   3   0   5   4

  -2   3   3  -3   1   3  -1  -4  -4   4  -1   0  -3  -1  -2   3

   3   2   0  -2   3   1  -3   2   1  -1  -1   1  -2   4   1  -3

  -2  -2   2   1  -4   3   3   4   4   2   1   4   5  -3   0  -3

   1   1  -2   5   3  -2   5  -2   2   5   1   0  -3   0   4   3

   4   4  -1   4  -2  -3   3   3   3  -3   2   1   5   3  -3   1

CROSSREFS

Sequence in context: A028218 A028199 A285236 * A255496 A098612 A268739

Adjacent sequences:  A208946 A208947 A208948 * A208950 A208951 A208952

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 03 2012

STATUS

approved

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Last modified May 18 18:24 EDT 2022. Contains 353823 sequences. (Running on oeis4.)