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A143094 Arises in counting relative Milnor rings in K-theory. 1
1, 2, 5, 15, 47, 145, 470 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Column 3 of Marshall table, p. 443. A143093 is the analogous enumeration, column 2 of Marshall table, if we view the K-structures as graded rings with distinguished element.

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 just as graded rings.

CROSSREFS

Cf. A143093.

Sequence in context: A148360 A148361 A148362 * A058495 A151280 A149914

Adjacent sequences:  A143091 A143092 A143093 * A143095 A143096 A143097

KEYWORD

more,nonn

AUTHOR

Jonathan Vos Post, Jul 23 2008

STATUS

approved

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Last modified December 19 07:12 EST 2014. Contains 252177 sequences.