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

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

Keyword

nonn

Author

Sharon Sela (sharonsela(AT)hotmail.com), Jan 04 2002

Extensions

a(7)-a(11) from Andrew Howroyd, Jul 02 2018

More terms from Robin Visser, Aug 09 2023

Status

approved