login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A038552 Largest squarefree number k such that Q(sqrt(-k)) has class number n. 6
163, 427, 907, 1555, 2683, 3763, 5923, 6307, 10627, 13843, 15667, 17803, 20563, 30067, 34483, 31243, 37123, 48427, 38707, 58507, 61483, 85507, 90787, 111763, 93307, 103027, 103387, 126043, 166147, 134467, 133387, 164803, 222643, 189883 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Probably all terms are odd, in which case this is also the largest absolute value of fundamental negative discriminant d for class number n.

Numbers so far are all 19 mod 24. - Ralf Stephan, Jul 07 2003

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..100

Duncan A. Buell, Small class numbers and extreme values of L-functions of quadratic fields, Math. Comp., 31 (1977), 786-796.

M. Watkins, Class numbers of imaginary quadratic fields, Mathematics of Computation 73 (2004), pp. 907-938.

Eric Weisstein's World of Mathematics, Class Number

MATHEMATICA

<< NumberTheory`NumberTheoryFunctions`; a = Table[0, {32} ]; Do[ If[ Mod[n, 4] != 1 || Mod[n, 4] != 2 || SquareFreeQ[n], c = ClassNumber[ -n]; If[c < 33, a[[c]] = n]], {n, 0, 250000} ]; a

CROSSREFS

Cf. A081319, A046125.

Sequence in context: A142427 A142237 A142283 * A127883 A054466 A221903

Adjacent sequences:  A038549 A038550 A038551 * A038553 A038554 A038555

KEYWORD

nonn,nice,hard

AUTHOR

Robert Brewer (rbrewerjr(AT)aol.com)

EXTENSIONS

More terms from Robert G. Wilson v, Nov 08 2001

2 more terms from Dean Hickerson, May 20 2003. The values were obtained by transcribing and combining data from Tables 1-3 of Buell's paper, which has information for all values of n up to 125.

Values checked against Watkins' data, which proves the values of a(n) for n = 1..100. Charles R Greathouse IV, Feb 08 2012

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 22 14:58 EST 2017. Contains 282487 sequences.