OFFSET
1,2
COMMENTS
For the discriminant of the quadratic field Q(sqrt(-n)), see A204993.
a(n) is the smallest positive N such that (n/k) = (n/(k mod N)) for every odd k that is coprime to n, where (n/k) is the Jacobi symbol. As we have Dirichlet's theorem on arithmetic progressions, a(n) is also the smallest positive N such that (n/p) = (n/(p mod N)) for every odd prime p that is not a factor of n. - Jianing Song, May 16 2024
LINKS
T. D. Noe, Table of n, a(n) for n = 1..1000
S. R. Finch, Class number theory
Steven R. Finch, Class number theory [Cached copy, with permission of the author]
FORMULA
Let b(n) = A007913(n), then a(n) = b(n) if b(n) == 1 (mod 4) and 4*b(n) otherwise. - Jianing Song, May 16 2024
MATHEMATICA
Table[NumberFieldDiscriminant[Sqrt[n]], {n, 100}] (* Artur Jasinski, Jan 27 2012 *)
PROG
(PARI) vector(150, n, quaddisc(n))
(Sage)
[fundamental_discriminant(n) for n in (1..69)] # Peter Luschny, Oct 15 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jason Earls, Jun 30 2001
STATUS
approved