A003647 Class number of real quadratic forms with discriminant 4n+1.
1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 2, 2, 1, 2, 2, 1, 2, 1, 1, 4, 1, 1, 2, 2, 1, 2, 4, 1, 1, 2, 4, 1, 2, 1, 2, 1, 1, 2, 4, 2, 2, 2, 4, 3, 1, 2, 1, 2, 2, 3, 2, 1, 4, 1, 1, 4, 1, 2, 4, 2, 1, 1, 6, 2, 1, 2, 4, 1, 1, 4, 2, 1, 4, 2, 4, 1, 2, 1, 5, 1, 2, 2, 1, 4, 1, 2, 4, 1, 2, 1, 1, 4, 6, 6, 2, 2, 2, 2, 2, 2, 8, 1, 2, 1
Offset: 1
Keywords
References
- D. A. Buell, Binary Quadratic Forms. Springer-Verlag, NY, 1989, pp. 224-241.
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Crossrefs
Cf. A003648.