A143093 - OEIS

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A143093

Arises in counting relative Milnor rings in K-theory.

1

1, 3, 6, 17, 51, 155, 492 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`0,2`
	COMMENTS	`Column 2 of Marshall table, p. 443. A143094 is the analogous enumeration, column 3 of Marshall table, if we view the K-structures just as graded rings.`
	REFERENCES	`Ido Efrat, Valuations, orderings and Milnor K-theory, Mathematical Surveys and Monographs, vol. 124, American Mathematical Society, 2006.` `Murray Marshall, Book Review: Valuations, orderings and Milnor K-theory, by Ido Efrat, Bulletin of the American Mathematical Society, Vol. 45 (July 2008) No. 3, pp. 439-444.`
	LINKS	`Table of n, a(n) for n=0..6.`
	FORMULA	`a(n) = the number of nonisomorphic elementary types K_*(F)/S with \|F^X/S\| = 2^n, if we view the K-structures as graded rings with distinguished element.`
	CROSSREFS	`Cf. A143094.` `Sequence in context: A360273 A287901 A354878 * A117712 A106158 A274103` `Adjacent sequences: A143090 A143091 A143092 * A143094 A143095 A143096`
	KEYWORD	`more,nonn`
	AUTHOR	`Jonathan Vos Post, Jul 23 2008`
	STATUS	`approved`

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Last modified March 23 03:31 EDT 2023. Contains 361434 sequences. (Running on oeis4.)