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A143093
Arises in counting relative Milnor rings in K-theory.
1
1, 3, 6, 17, 51, 155, 492
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.
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
KEYWORD
more,nonn
AUTHOR
Jonathan Vos Post, Jul 23 2008
STATUS
approved