A102270 2-class number of Q(sqrt(-21p)) as p runs through primes in A102269.

16, 8, 8, 8, 16, 8, 16, 16, 16, 8, 16, 32, 8, 8, 8, 8, 32, 8, 16, 64, 32, 8, 32, 8, 8, 128, 32, 32, 32, 16, 8, 8, 8, 16, 16, 8, 8, 8, 128, 16, 8, 8, 16, 32, 8, 16, 32, 8, 8, 8, 128, 8, 8, 8, 16, 8, 64, 8, 8, 8, 16, 8, 16, 16, 16, 8, 8, 16, 32, 16, 8, 8, 8, 64, 32, 64, 16, 64, 8, 16, 32

Offset

1,1

Links

Table of n, a(n) for n=1..81.

H. Cohn and J. C. Lagarias, On the existence of fields governing the 2-invariants of the classgroup of Q(sqrt{dp}) as p varies, Math. Comp. 41 (1983), 711-730.

Prog

(Sage) [2^QuadraticField(-21*p).class_number().valuation(2) for p in Primes()[:1000] if (p%84) in [43, 67, 79]] # Robin Visser, Mar 13 2024

Crossrefs

Cf. A102269, A102271, A102272, A102273, A102274, A102275.

Sequence in context: A033336 A204325 A355873 * A102272 A304227 A305037

Adjacent sequences: A102267 A102268 A102269 * A102271 A102272 A102273

Keyword

nonn

Author

N. J. A. Sloane, Feb 19 2005

Extensions

More terms from Robin Visser, Mar 13 2024

Status

approved