/*
www-ATLAS of Group Representations.
3.A7 represented as 21 x 21 matrices over GF(25).
*/

F<w>:=GF(25);

x:=CambridgeMatrix(3,F,21,\[
0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,
0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,
10,12,23,17,24,21,10,17,8,8,10,23,21,5,19,2,5,15,10,2,2,
0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
7,24,24,17,12,24,10,21,9,8,7,16,16,14,11,21,24,7,4,5,3,
19,23,17,12,3,23,8,5,2,9,14,22,10,15,11,16,14,7,13,20,22,
9,6,5,12,10,20,0,9,21,8,9,1,23,12,3,16,14,12,22,18,16,
18,14,15,1,24,9,13,7,11,24,24,9,0,5,13,10,12,6,16,2,23,
4,1,9,4,15,1,24,10,19,23,7,4,11,24,22,13,14,18,18,20,15,
23,1,20,11,14,13,12,10,5,22,13,13,22,5,19,17,7,16,13,4,14,
0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0]);

y:=CambridgeMatrix(3,F,21,\[
22,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,
17,3,24,19,24,22,20,8,18,20,14,5,23,17,20,24,8,8,0,11,23,
5,19,0,2,0,0,18,0,0,0,0,0,8,0,0,0,0,0,0,0,0,
14,3,0,18,24,11,0,5,4,13,3,7,15,24,15,13,8,18,14,2,6,
17,19,9,10,11,17,10,12,20,14,14,23,10,18,22,9,15,24,7,5,15,
1,15,19,7,16,24,11,22,2,17,15,6,4,4,0,21,11,6,5,23,7,
4,23,8,0,24,16,21,6,19,0,10,6,23,8,16,10,7,14,9,11,22,
14,14,8,21,16,13,20,17,3,18,6,5,0,18,12,16,2,13,11,8,7,
5,19,14,9,12,23,14,14,11,1,4,11,15,2,4,2,0,5,8,8,6,
16,6,20,12,14,21,21,9,17,8,16,5,7,23,1,13,8,2,2,1,11,
10,14,7,13,4,9,12,19,18,9,23,7,11,15,18,11,13,5,15,1,15]);

G<x,y>:=MatrixGroup<21,F|x,y>;
print "Group G is 3.A7 < GL(21,GF(25))";