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 A104137 Number of distinct necklaces with p beads of two possible colors, allowing turning over, p being a prime greater than 2. 0
 4, 8, 18, 126, 380, 4112, 14310, 184410, 9272780, 34669602, 1857545300, 26818405352, 102282248574, 1497215711538, 84973644983780, 4885261149611790, 18900353608280300, 1101298162244236182, 16628051030379615882 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS For the general necklace problem, see A000029. REFERENCES Martin Gardner, The Colossal Book of Mathematics, pp. 19, W. W. Norton & Co., NY 2001 (or, New Mathematical Diversions, pp. 243-4 MAA Washington DC 1995). LINKS FORMULA a(n) = (2^(p-1) - 1)/p + 2^{(p-1)/2} + 1 = A007663(n) + A061285(n) + 1. MAPLE for p from 2 to 30 do printf(`%d, `, (2^(ithprime(p)-1)-1)/ithprime(p) + 2^((ithprime(p)-1)/2) + 1) od: # James A. Sellers, Apr 10 2005 CROSSREFS Cf. A000029. Sequence in context: A075310 A075797 A351323 * A308563 A272110 A272542 Adjacent sequences: A104134 A104135 A104136 * A104138 A104139 A104140 KEYWORD nonn AUTHOR Lekraj Beedassy, Mar 07 2005 EXTENSIONS More terms from James A. Sellers, Apr 10 2005 STATUS approved

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Last modified December 8 08:22 EST 2022. Contains 358693 sequences. (Running on oeis4.)