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A018229 Numbers n such that normalizer of Gamma_0(n) is triangle group (2,4,inf). 3
2, 8, 18, 32, 72, 128, 288, 1152 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

REFERENCES

Akbas and Singerman, The signature of the normalizer..., in Graphs, Combinatorics and Geometry, ed. Liebeck and Saxl, LMSLNS 165, Cambridge Univ. Press, 1992, 77-86.

CROSSREFS

Cf. A018228, A018230, A018231.

Sequence in context: A050804 A081324 A190787 * A166830 A072779 A198014

Adjacent sequences:  A018226 A018227 A018228 * A018230 A018231 A018232

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

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Last modified February 15 10:06 EST 2012. Contains 205763 sequences.