

A005472


Class numbers of cubic fields.
(Formerly M3291)


2



1, 1, 1, 1, 1, 1, 1, 4, 7, 4, 4, 4, 7, 4, 13, 7, 19, 7, 7, 7, 19, 19, 19, 16, 31, 19, 28, 19, 49, 31, 28, 31, 64, 43, 37, 127, 61, 52, 52, 52, 49, 100, 37, 112, 64, 67, 61, 76, 61, 76, 61, 61, 112, 76, 73, 67, 133, 91, 223, 169, 73, 112, 100, 169, 91, 121, 175
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OFFSET

1,8


COMMENTS

Class numbers of cubic fields with discriminants p^2, where p runs through the primes in A005471.
All terms are of the form a^2 + 3*b^2.  Colin Barker, Nov 30 2014


REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS

R. J. Mathar, Table of n, a(n) for n = 1..100
D. Shanks, The simplest cubic fields, Math. Comp., 28 (1974), 11371152 (see Table 1 page 1140).


CROSSREFS

Sequence in context: A020803 A019626 A203137 * A111522 A019735 A202501
Adjacent sequences: A005469 A005470 A005471 * A005473 A005474 A005475


KEYWORD

nonn


AUTHOR

N. J. A. Sloane


STATUS

approved



