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G = C8.21D8order 128 = 27

12nd non-split extension by C8 of D8 acting via D8/C8=C2

p-group, metabelian, nilpotent (class 4), monomial

Aliases: C8.21D8, C16.12D4, C42.339D4, (C4×C16)⋊11C2, (C2×Q32)⋊6C2, C8.42(C2×D4), (C2×C4).63D8, C4.10(C2×D8), (C2×D16).3C2, (C2×C8).280D4, (C2×SD32)⋊17C2, C8.12D42C2, C4.4(C41D4), C2.18(C4○D16), C2.15(C84D4), (C4×C8).414C22, (C2×C8).547C23, (C2×C16).85C22, (C2×D8).18C22, C22.133(C2×D8), (C2×Q16).19C22, (C2×C4).815(C2×D4), SmallGroup(128,981)

Series: Derived Chief Lower central Upper central Jennings

C1C2×C8 — C8.21D8
C1C2C4C2×C4C2×C8C4×C8C4×C16 — C8.21D8
C1C2C4C2×C8 — C8.21D8
C1C22C42C4×C8 — C8.21D8
C1C2C2C2C2C4C4C2×C8 — C8.21D8

Generators and relations for C8.21D8
 G = < a,b,c | a8=c2=1, b8=a4, ab=ba, cac=a3, cbc=a4b7 >

Subgroups: 264 in 92 conjugacy classes, 36 normal (18 characteristic)
C1, C2, C2, C2, C4, C4, C22, C22, C8, C8, C2×C4, C2×C4, C2×C4, D4, Q8, C23, C16, C42, C22⋊C4, C2×C8, D8, SD16, Q16, C2×D4, C2×Q8, C4×C8, C2×C16, D16, SD32, Q32, C4.4D4, C2×D8, C2×SD16, C2×Q16, C4×C16, C8.12D4, C2×D16, C2×SD32, C2×Q32, C8.21D8
Quotients: C1, C2, C22, D4, C23, D8, C2×D4, C41D4, C2×D8, C84D4, C4○D16, C8.21D8

Smallest permutation representation of C8.21D8
On 64 points
Generators in S64
(1 51 30 45 9 59 22 37)(2 52 31 46 10 60 23 38)(3 53 32 47 11 61 24 39)(4 54 17 48 12 62 25 40)(5 55 18 33 13 63 26 41)(6 56 19 34 14 64 27 42)(7 57 20 35 15 49 28 43)(8 58 21 36 16 50 29 44)
(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16)(17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32)(33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48)(49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64)
(1 16)(2 15)(3 14)(4 13)(5 12)(6 11)(7 10)(8 9)(17 18)(19 32)(20 31)(21 30)(22 29)(23 28)(24 27)(25 26)(33 62)(34 61)(35 60)(36 59)(37 58)(38 57)(39 56)(40 55)(41 54)(42 53)(43 52)(44 51)(45 50)(46 49)(47 64)(48 63)

G:=sub<Sym(64)| (1,51,30,45,9,59,22,37)(2,52,31,46,10,60,23,38)(3,53,32,47,11,61,24,39)(4,54,17,48,12,62,25,40)(5,55,18,33,13,63,26,41)(6,56,19,34,14,64,27,42)(7,57,20,35,15,49,28,43)(8,58,21,36,16,50,29,44), (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16)(17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32)(33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48)(49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64), (1,16)(2,15)(3,14)(4,13)(5,12)(6,11)(7,10)(8,9)(17,18)(19,32)(20,31)(21,30)(22,29)(23,28)(24,27)(25,26)(33,62)(34,61)(35,60)(36,59)(37,58)(38,57)(39,56)(40,55)(41,54)(42,53)(43,52)(44,51)(45,50)(46,49)(47,64)(48,63)>;

G:=Group( (1,51,30,45,9,59,22,37)(2,52,31,46,10,60,23,38)(3,53,32,47,11,61,24,39)(4,54,17,48,12,62,25,40)(5,55,18,33,13,63,26,41)(6,56,19,34,14,64,27,42)(7,57,20,35,15,49,28,43)(8,58,21,36,16,50,29,44), (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16)(17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32)(33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48)(49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64), (1,16)(2,15)(3,14)(4,13)(5,12)(6,11)(7,10)(8,9)(17,18)(19,32)(20,31)(21,30)(22,29)(23,28)(24,27)(25,26)(33,62)(34,61)(35,60)(36,59)(37,58)(38,57)(39,56)(40,55)(41,54)(42,53)(43,52)(44,51)(45,50)(46,49)(47,64)(48,63) );

G=PermutationGroup([[(1,51,30,45,9,59,22,37),(2,52,31,46,10,60,23,38),(3,53,32,47,11,61,24,39),(4,54,17,48,12,62,25,40),(5,55,18,33,13,63,26,41),(6,56,19,34,14,64,27,42),(7,57,20,35,15,49,28,43),(8,58,21,36,16,50,29,44)], [(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16),(17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32),(33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48),(49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64)], [(1,16),(2,15),(3,14),(4,13),(5,12),(6,11),(7,10),(8,9),(17,18),(19,32),(20,31),(21,30),(22,29),(23,28),(24,27),(25,26),(33,62),(34,61),(35,60),(36,59),(37,58),(38,57),(39,56),(40,55),(41,54),(42,53),(43,52),(44,51),(45,50),(46,49),(47,64),(48,63)]])

38 conjugacy classes

class 1 2A2B2C2D2E4A···4F4G4H8A···8H16A···16P
order1222224···4448···816···16
size111116162···216162···22···2

38 irreducible representations

dim111111222222
type+++++++++++
imageC1C2C2C2C2C2D4D4D4D8D8C4○D16
kernelC8.21D8C4×C16C8.12D4C2×D16C2×SD32C2×Q32C16C42C2×C8C8C2×C4C2
# reps1121214114416

Matrix representation of C8.21D8 in GL4(𝔽17) generated by

161500
1100
00107
0050
,
16000
01600
00712
00112
,
16000
1100
00712
001310
G:=sub<GL(4,GF(17))| [16,1,0,0,15,1,0,0,0,0,10,5,0,0,7,0],[16,0,0,0,0,16,0,0,0,0,7,11,0,0,12,2],[16,1,0,0,0,1,0,0,0,0,7,13,0,0,12,10] >;

C8.21D8 in GAP, Magma, Sage, TeX

C_8._{21}D_8
% in TeX

G:=Group("C8.21D8");
// GroupNames label

G:=SmallGroup(128,981);
// by ID

G=gap.SmallGroup(128,981);
# by ID

G:=PCGroup([7,-2,2,2,-2,2,-2,-2,141,288,422,436,1123,360,4037,124]);
// Polycyclic

G:=Group<a,b,c|a^8=c^2=1,b^8=a^4,a*b=b*a,c*a*c=a^3,c*b*c=a^4*b^7>;
// generators/relations

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