|
|
A065128
|
|
Number of invertible n X n matrices mod 4 (i.e., over the ring Z_4).
|
|
4
|
|
|
1, 2, 96, 86016, 1321205760, 335522845163520, 1385295986380096143360, 92239345887620476544860815360, 98654363640526679389774053813465907200, 1691558770638735027870457216848672340872423014400, 464518059995994038184379206447729320401459864818351813427200
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
|
|
FORMULA
|
a(n) = 4^(n^2) * Product_{k=1..n} (1 - 1/2^k).
|
|
MATHEMATICA
|
a(0) = 1. a[n_] := 4^(n^2)*Product[1 - 1/2^k, {k, 1, n} ]; Table[ a[n], {n, 0, 10} ]
|
|
PROG
|
(PARI) for(n=1, 11, print(4^(n^2)*prod(k=1, n, (1-1/2^k))))
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Dan Fux (dan.fux(AT)OpenGaia.com or danfux(AT)OpenGaia.com), Nov 14 2001
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|