cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A102264 Smallest prime for which 2^n exactly divides the class number h(-4p).

Original entry on oeis.org

5, 17, 41, 257, 521, 4481, 9521, 21929, 72089, 531977, 1256009, 5014169, 20879129, 70993529, 258844361, 866941841, 3771185921, 13949589209, 57388297721
Offset: 1

Views

Author

N. J. A. Sloane, Feb 19 2005

Keywords

Crossrefs

Cf. A006641.

Programs

  • Sage
    def a(n):
        for p in Primes():
            if QuadraticField(-p).class_number().valuation(2)==n:
                return p  # Robin Visser, May 25 2024

Extensions

a(10)-a(17) from Robin Visser, May 25 2024
a(18)-a(19) from Robin Visser, Dec 28 2024