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

Author

N. J. A. Sloane, Feb 19 2005

Keywords

• nonn

Links

• 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.

Crossrefs

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

Programs

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

Extensions

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