%I #16 Aug 23 2013 13:57:33
%S 1,21,673,102273,47663617,110981851137,815432848809985,
%T 30052835284679819265,3519512226295269640765441,
%U 2069751512310185039905834926081,3874510079394593253089862950754189313,36431456010689490638771956423547489198538753
%N Number of involutions in GL(n,4).
%H Alois P. Heinz, <a href="/A211877/b211877.txt">Table of n, a(n) for n = 1..50</a>
%p A211877 := proc(n)
%p add( 4^(k*(n-k))*A022168(n,k),k=1..n) ;
%p end proc: # _R. J. Mathar_, Apr 26 2013
%t Sum[q^(k (n - k)) QBinomial[n, k, q], {k, 1, n}]
%K nonn
%O 1,2
%A _Alexander Gruber_, Feb 12 2013