OFFSET
0,9
COMMENTS
All rows are multiplicative.
Equivalently, the number of n X n matrices mod k with determinant 1.
Also, for k prime (but not higher prime powers) the number of n X n matrices over GF(k) with determinant 1.
LINKS
R. P. Brent and B. D. McKay, Determinants and ranks of random matrices over Zm, Discrete Mathematics 66 (1987) pp. 35-49.
J. M. Lockhart and W. P. Wardlaw, Determinants of Matrices over the Integers Modulo m, Mathematics Magazine, Vol. 80, No. 3 (Jun., 2007), pp. 207-214.
The Group Properties Wiki, Order formulas for linear groups
FORMULA
T(n,p^e) = (p^e)^(n^2-1) * Product_{j=2..n} (1 - 1/p^j) for prime p, n > 0.
EXAMPLE
Array begins:
==============================================================
n\k| 1 2 3 4 5 6
---+----------------------------------------------------------
0 | 1 1 1 1 1 1 ...
1 | 1 1 1 1 1 1 ...
2 | 1 6 24 48 120 144 ...
3 | 1 168 5616 43008 372000 943488 ...
4 | 1 20160 12130560 660602880 29016000000 244552089600 ...
5 | 1 9999360 ...
...
MATHEMATICA
T[n_, k_] := If[k == 1 || n == 0, 1, k^(n^2-1) Product[1 - p^-j, {p, FactorInteger[k][[All, 1]]}, {j, 2, n}]];
Table[T[n-k+1, k], {n, 0, 8}, {k, n+1, 1, -1}] // Flatten (* Jean-François Alcover, Sep 19 2019 *)
PROG
(GAP)
T:=function(n, k) if k=1 or n=0 then return 1; else return Order(SL(n, Integers mod k)); fi; end;
for n in [0..5] do Print(List([1..6], k->T(n, k)), "\n"); od;
(PARI) T(n, k)={my(f=factor(k)); if(n<1, n==0, k^(n^2-1) * prod(i=1, #f~, my(p=f[i, 1]); prod(j=2, n, (1 - p^(-j)))))}
CROSSREFS
KEYWORD
AUTHOR
Andrew Howroyd, Jul 08 2018
STATUS
approved