A143093 - OEIS

%I #14 Apr 03 2014 22:05:56

%S 1,3,6,17,51,155,492

%N Arises in counting relative Milnor rings in K-theory.

%C 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.

%D Ido Efrat, Valuations, orderings and Milnor K-theory, Mathematical Surveys and Monographs, vol. 124, American Mathematical Society, 2006.

%D 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.

%F 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.

%Y Cf. A143094.

%K more,nonn

%O 0,2

%A _Jonathan Vos Post_, Jul 23 2008