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A061653 Relative class number h- of cyclotomic field Q(zeta_n). +0
5
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 8, 1, 9, 1, 1, 1, 1, 1, 37, 1, 2, 1, 121, 1, 211, 1, 1, 3, 695, 1, 43, 1, 5, 3, 4889, 1, 10, 2, 9, 8, 41421, 1, 76301, 9, 7, 17, 64, 1, 853513, 8, 69, 1, 3882809, 3, 11957417, 37, 11, 19, 1280, 2, 100146415 (list; graph; listen)
OFFSET

1,23

COMMENT

Note that if n == 2 (mod 4), Q(zeta_n) is the same field as Q(zeta_{n/2}).

REFERENCES

L. C. Washington, Introduction to Cyclotomic Fields, Springer, p. 353.

LINKS

R. J. Mathar, Table of n, a(n) for n = 1..162

EXAMPLE

Q(zeta_23) = 3 is the first time that h- is bigger than 1.

CROSSREFS

Cf. A035115, A055513, A061494, A005848.

Sequence in context: A046556 A046535 A135939 this_sequence A069226 A016565 A051714

Adjacent sequences: A061650 A061651 A061652 this_sequence A061654 A061655 A061656

KEYWORD

nonn,easy,nice

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Jun 16 2001

EXTENSIONS

Washington gives an extensive table on pp. 353-360.

Missing term a(1) = 1 inserted by N. J. A. Sloane (njas(AT)research.att.com), Feb 05 2009 at the suggestion of Tanya Khovanova

More terms from R. J. Mathar, Feb 06 2009

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Last modified November 25 14:49 EST 2009. Contains 167514 sequences.


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