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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: A204517 A307685 A287901 * A117712 A003323 A106158

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 December 14 17:32 EST 2019. Contains 329979 sequences. (Running on oeis4.)