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A106029
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a(n) is the number of orbits under the action of GL_2[Z] on the primitive binary quadratic forms of discriminant D, where D=m if m=1 (mod 4), D=4*m otherwise and m<0 is the n-th squarefree number.
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0
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1, 1, 1, 2, 2, 1, 2, 1, 2, 3, 2, 3, 1, 4, 2, 2, 4, 4, 4, 2, 4, 3, 2, 2, 4, 3, 5, 4, 1, 3, 3, 2, 4, 3, 4, 2, 2, 4, 5, 6, 6, 1, 6, 4, 4, 3, 6, 6, 4, 3, 3, 2, 4, 6, 4, 7, 2, 4, 5, 5, 3
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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COMMENTS
| A000924 is the same except it is under the action of SL_2[Z].
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LINKS
| S. R. Finch, Class number theory
Jens Jonasson, Classes of integral binary quadratic forms, Masters thesis (2001), Appendix B.
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EXAMPLE
| m=-1, -2, -3, -5, -6, -7, -10, -11, -13, ...
with corresponding discriminant
D=-4, -8, -3, -20, -24, -7, -40, -11, -52, ....
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CROSSREFS
| Cf. A000924.
Sequence in context: A024880 A029424 A061498 * A188431 A105153 A000924
Adjacent sequences: A106026 A106027 A106028 * A106030 A106031 A106032
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KEYWORD
| nonn
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AUTHOR
| S. R. Finch (Steven.Finch(AT)inria.fr), May 05 2005
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