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A018231
Numbers n such that normalizer of Gamma_0(n) is a triangle group.
3
1, 2, 3, 4, 8, 9, 12, 16, 18, 27, 32, 36, 48, 64, 72, 108, 128, 144, 192, 256, 288, 432, 576, 1152, 1728, 2304
OFFSET
1,2
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.
CROSSREFS
KEYWORD
nonn,fini,full
AUTHOR
EXTENSIONS
Missing terms 256 and 2304 added, list sorted, and keywords added by Sean A. Irvine, Feb 05 2019
STATUS
approved