A367669 - OEIS

A367669

Number of degree 3 number fields unramified outside the first n prime numbers.

0, 9, 32, 108, 360, 1168, 3638, 11492, 35638, 111059

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OFFSET

1,2

COMMENTS

B. Matschke showed that a(11) = 340618 assuming the Generalized Riemann Hypothesis.

LINKS

Table of n, a(n) for n=1..10.

K. Belabas, A fast algorithm to compute cubic fields, Math. Comp. 66 (1997), no. 219, 1213-1237.

J. W. Jones and D. P. Roberts, A database of number fields, LMS J. Comput. Math. 17 (2014), no. 1, 595-618.

B. Matschke, Number fields unramified outside S.

EXAMPLE

For n = 1, there are no cubic number fields unramified away from 2, so a(1) = 0.

For n = 2, the a(2) = 9 cubic number fields unramified away from {2,3} can be given by Q(a) where a is a root of x^3 - 3x - 1, x^3 - 2, x^3 + 3x - 2, x^3 - 3, x^3 - 3x - 4, x^3 - 3x - 10, x^3 - 12, x^3 - 6, or x^3 - 9x - 6.

CROSSREFS

Cf. A126646 (degree 2), A368057 (degree 4).

Sequence in context: A326247 A362526 A225918 * A231999 A297298 A229444

Adjacent sequences: A367666 A367667 A367668 * A367670 A367671 A367672

KEYWORD

nonn,more

AUTHOR

Robin Visser, Nov 26 2023

STATUS

approved