OFFSET
1,2
COMMENTS
Here two matrices A, B in SL(2, Z_n) are in the same conjugacy class if P^-1*A*P = B for some matrix P in GL(2, Z_n).
FORMULA
For an odd prime p : a(p) = p + 2.
PROG
(Magma) [#[c[3] : c in Classes(GL(2, ResidueClassRing(n))) | Determinant(c[3]) eq 1] : n in [2..50]];
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
Robin Visser, Aug 10 2023
STATUS
approved