A004075 - OEIS

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A004075

Number of Skolem sequences of order n.

1, 0, 0, 6, 10, 0, 0, 504, 2656, 0, 0, 455936, 3040560, 0, 0, 1400156768, 12248982496, 0, 0, 11435578798976, 123564928167168, 0, 0 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,4`
	COMMENTS	`For n>1, a(n)=A059106(n)*2 because A059106 ignores reflected solutions. - Martin Fuller (martin_n_fuller(AT)btinternet.com), Mar 08 2007`
	REFERENCES	`CRC Handbook of Combinatorial Designs, 1996, p. 460.`
	LINKS	`G. Nordh, Perfect Skolem sequences` `J. E. Miller, Langford's Problem`
	CROSSREFS	`Cf. A059106.` `Sequence in context: A061110 A110460 A159190 * A202951 A052193 A144763` `Adjacent sequences: A004072 A004073 A004074 * A004076 A004077 A004078`
	KEYWORD	`nonn`
	AUTHOR	`N. J. A. Sloane (njas(AT)research.att.com).`
	EXTENSIONS	`More terms (via A059106) from Martin Fuller (martin_n_fuller(AT)btinternet.com), Mar 08 2007`

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Last modified February 16 16:45 EST 2012. Contains 205938 sequences.