A066514 - OEIS

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A066514

Number of subgroups of the group GL(2,Z_n) of invertible 2 X 2 matrices mod n (sequence A000252).

1, 6, 55, 234, 466, 758, 1704, 24587, 6656, 6718, 6428, 114210, 17158, 26180, 135869, 701426, 33277, 126920, 52320, 1341656, 469872, 87924, 48976, 50257306, 140918, 291060, 348528, 3952920, 175438, 3685062, 285952, 12024029, 1657948, 567994, 4624192, 15262640, 539046, 838096

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..38.

PROG

(GAP) c := CyclicGroup(n); aut := AutomorphismGroup(DirectProduct(c, c)); lat := LatticeSubgroups(aut);

(Magma) [&+[s`length : s in Subgroups(GL(2, ResidueClassRing(n)))] : n in [2..10]]; // Robin Visser, Aug 09 2023

CROSSREFS

Cf. A000252.

Sequence in context: A069508 A079465 A061792 * A281075 A009577 A097300

Adjacent sequences: A066511 A066512 A066513 * A066515 A066516 A066517