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 A309673 Number of n-bead necklace structures using a maximum of four different colored beads and no adjacent beads having the same color. 4
 0, 1, 1, 3, 2, 9, 13, 41, 94, 257, 671, 1881, 5110, 14301, 39871, 112281, 316520, 897297, 2548819, 7265383, 20754748, 59437181, 170549237, 490338539, 1412147684, 4073528481, 11767897903, 34042917197, 98606864030, 285960106473, 830206177801, 2412787265021 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Colors may be permuted without changing the necklace structure. LINKS Andrew Howroyd, Table of n, a(n) for n = 1..200 FORMULA a(n) = Sum_{k=1..4} A327396(n, k). CROSSREFS Cf. A056292, A306888, A327396, A328130. Sequence in context: A077898 A303631 A076584 * A154343 A049969 A088634 Adjacent sequences:  A309670 A309671 A309672 * A309674 A309675 A309676 KEYWORD nonn AUTHOR Andrew Howroyd, Oct 05 2019 EXTENSIONS Terms a(24) and beyond from Andrew Howroyd, Oct 10 2019 STATUS approved

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Last modified November 30 19:02 EST 2021. Contains 349424 sequences. (Running on oeis4.)