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A018230 Numbers n such that normalizer of Gamma_0(n) is triangle group (2,6,inf). 3
3, 12, 27, 48, 108, 192, 432, 1728 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

M. Akbas and D. Singerman, The signature of the normalizer Gamma_0(N), in Graphs, Combinatorics and Geometry, ed. Liebeck and Saxl, LMSLNS 165, Cambridge Univ. Press, 1992, 77-86.

LINKS

Table of n, a(n) for n=1..8.

CROSSREFS

Cf. A018229, A018228, A018231.

Sequence in context: A074630 A033428 A213486 * A058034 A294416 A187273

Adjacent sequences:  A018227 A018228 A018229 * A018231 A018232 A018233

KEYWORD

nonn,fini,full

AUTHOR

N. J. A. Sloane.

EXTENSIONS

Corrected Apr 15 1997.

Keywords added by Sean A. Irvine, Feb 05 2019

STATUS

approved

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Last modified July 26 20:17 EDT 2021. Contains 346294 sequences. (Running on oeis4.)