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Number of conjugacy classes in the group GL_2(K) when K is a finite field with q = p^m for a prime p and m >= 1.
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%I #5 Dec 04 2022 16:33:03

%S 3,8,15,24,48,63,80,120,168,255,288,360,528,624,728,840,960,1023,1368,

%T 1680,1848,2208,2400,2808,3480,3720,4095,4488,5040,5328,6240,6560,

%U 6888,7920,9408,10200,10608,11448,11880,12768,14640,15624,16128,16383,17160

%N Number of conjugacy classes in the group GL_2(K) when K is a finite field with q = p^m for a prime p and m >= 1.

%C The number of conjugacy classes in the group GL_2(K) is q^2 - 1 so this sequence is a subsequence of A005563 restricted to q = prime power. The order of the group GL_2(K) is in A059238.

%F a(n) = A000961(n+2)^2 - 1. - _Sean A. Irvine_, Dec 04 2022

%p with(numtheory): for n from 2 to 400 do if nops(ifactors(n)[2]) = 1 then printf(`%d,`, n^2-1) fi: od:

%Y A000961, A005563, A059238. A diagonal of A060638.

%K nonn

%O 0,1

%A Ahmed Fares (ahmedfares(AT)my-deja.com), Apr 13 2001

%E More terms from _James A. Sellers_, Apr 14 2001