A143094 Arises in counting relative Milnor rings in K-theory.

1, 2, 5, 15, 47, 145, 470

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: A148361 A346521 A148362 * A308274 A058495 A287275

Adjacent sequences: A143091 A143092 A143093 * A143095 A143096 A143097

Keyword

more,nonn

Author

Jonathan Vos Post, Jul 23 2008

Status

approved