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A208721 T(n,k) = number of n-bead necklaces labeled with numbers 1..k allowing reversal, with no adjacent beads differing by more than 1. 8
1, 2, 1, 3, 3, 1, 4, 5, 4, 1, 5, 7, 7, 6, 1, 6, 9, 10, 12, 8, 1, 7, 11, 13, 18, 18, 13, 1, 8, 13, 16, 24, 28, 34, 18, 1, 9, 15, 19, 30, 38, 56, 56, 30, 1, 10, 17, 22, 36, 48, 78, 98, 111, 46, 1, 11, 19, 25, 42, 58, 100, 140, 208, 207, 78, 1, 12, 21, 28, 48, 68, 122, 182, 306, 418, 427, 126 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Table starts

.1..2...3...4...5...6...7...8...9..10..11..12...13...14...15...16...17...18

.1..3...5...7...9..11..13..15..17..19..21..23...25...27...29...31...33...35

.1..4...7..10..13..16..19..22..25..28..31..34...37...40...43...46...49...52

.1..6..12..18..24..30..36..42..48..54..60..66...72...78...84...90...96..102

.1..8..18..28..38..48..58..68..78..88..98.108..118..128..138..148..158..168

.1.13..34..56..78.100.122.144.166.188.210.232..254..276..298..320..342..364

.1.18..56..98.140.182.224.266.308.350.392.434..476..518..560..602..644..686

.1.30.111.208.306.404.502.600.698.796.894.992.1090.1188.1286.1384.1482.1580

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..397

EXAMPLE

All solutions for n=4, k=3:

..2....3....2....2....1....2....1....2....1....1....1....1

..3....3....2....3....1....2....1....2....2....2....1....2

..2....3....3....3....2....2....1....2....1....3....1....2

..3....3....3....3....2....2....1....3....2....2....2....2

CROSSREFS

Column 2 is A000029.

Sequence in context: A286312 A278492 A128139 * A208777 A104732 A132108

Adjacent sequences:  A208718 A208719 A208720 * A208722 A208723 A208724

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin, Mar 01 2012

STATUS

approved

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Last modified March 20 09:35 EDT 2019. Contains 321345 sequences. (Running on oeis4.)