This site is supported by donations to The OEIS Foundation.

The October issue of the Notices of the Amer. Math. Soc. has an article about the OEIS.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A208720 Number of n-bead necklaces labeled with numbers 1..7 allowing reversal, with no adjacent beads differing by more than 1. 1
 7, 13, 19, 36, 58, 122, 224, 502, 1066, 2528, 5902, 14717, 36557, 93987, 242387, 635990, 1675743, 4457771, 11903835, 31970464, 86144382, 233001926, 631920076, 1718567054, 4684178054, 12794677456, 35012475762, 95976563897, 263496604025, 724445459431 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Andrew Howroyd, Table of n, a(n) for n = 1..100 FORMULA a(2n+1) = (1/2) * (A208776(2n+1) + A002714(n+1)). - Andrew Howroyd, Mar 03 2017 a(2n) = (1/2) * A208776(2n) + (1/4) * (A002714(n) + A002714(n+1)). - Andrew Howroyd, Mar 03 2017 EXAMPLE All solutions for n=3: ..1....1....6....3....6....5....2....4....4....3....5....4....5....7....6....2 ..2....1....6....4....7....5....3....4....5....3....6....4....5....7....6....2 ..2....1....7....4....7....5....3....5....5....3....6....4....6....7....6....3 .. ..1....2....3 ..1....2....3 ..2....2....4 CROSSREFS Column 7 of A208721. Cf. A208776, A002714. Sequence in context: A283191 A048375 A198035 * A208776 A108295 A071923 Adjacent sequences:  A208717 A208718 A208719 * A208721 A208722 A208723 KEYWORD nonn AUTHOR R. H. Hardin, Mar 01 2012 EXTENSIONS a(22)-a(30) from Andrew Howroyd, Mar 03 2017 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 22 20:30 EDT 2018. Contains 315270 sequences. (Running on oeis4.)