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A091730 Norms of irreducible elements of Z[sqrt(-5)]. 2
4, 5, 6, 9, 14, 21, 29, 41, 46, 49, 61, 69, 86, 89, 94, 101, 109, 121, 129, 134, 141, 149, 161, 166, 169, 181, 201, 206, 214, 229, 241, 249, 254, 269, 281, 289, 301, 309, 321, 326, 329, 334, 349, 361, 381, 389, 401, 409, 421, 446, 449, 454, 461, 469, 489 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
The following lists the types of numbers which appear (p,q are distinct primes, congruences are mod 20 and the number in square brackets gives the number of irreducible elements of that norm counting a and -a only once): 4 [1]; 5 [1]; p==1,9 [2]; p^2 where p==-1,-3,-7,-9 [1]; 2p where p==3,7 [2]; p^2 where p==3,7 [3]; pq where p,q==3,7 [4].
REFERENCES
David A. Cox, Primes of the form x^2+ny^2, Wiley, 1989.
A. Frohlich and M. J. Taylor, Algebraic number theory, Cambridge university press, 1991.
LINKS
CROSSREFS
Sequence in context: A039013 A241511 A020669 * A058076 A238712 A033819
KEYWORD
easy,nonn
AUTHOR
Paul Boddington, Feb 02 2004
STATUS
approved

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Last modified June 20 23:18 EDT 2024. Contains 373535 sequences. (Running on oeis4.)