A102275 2-class number of Q(sqrt(-21p)) as p runs through primes in A102274.

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

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 [47, 59, 83]] # Robin Visser, Mar 13 2024

Crossrefs

Cf. A102269, A102270, A102271, A102272, A102273, A102274.

Sequence in context: A269999 A298944 A230309 * A299448 A300086 A115948

Adjacent sequences: A102272 A102273 A102274 * A102276 A102277 A102278

Keyword

nonn

Author

N. J. A. Sloane, Feb 19 2005

Extensions

a(19) corrected and more terms from Robin Visser, Mar 13 2024

Status

approved