%I A002820 M2170 N0866
%S A002820 2,48,5824,2887680,5821595648,47317927329792,1544457148312846336,
%T A002820 202039706313624586813440,105823549214125066767168438272,
%U A002820 221819704567105547916502447159246848
%N A002820 Number of n X n invertible binary matrices A such that A+I is invertible.
%D A002820 P. F. Duvall, Jr. and P. W. Harley, III, A note on counting matrices, 
               SIAM J. Appl. Math., 20 (1971), 374-377.
%D A002820 Kent E. Morrison, Integer Sequences and Matrices Over Finite Fields, 
               Journal of Integer Sequences, Vol. 9 (2006), Article 06.2.1.
%D A002820 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A002820 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%H A002820 Kent Morrison, <a href="http://www.calpoly.edu/~kmorriso/Research/mnev01.pdf">
               Matrices over F_q with no eigenvalues of 0 or 1</a>
%H A002820 <a href="Sindx_Mat.html#binmat">Index entries for sequences related to 
               binary matrices</a>
%F A002820 Reference gives a recurrence.
%F A002820 2^[n(n-1)/2] * A005327(n+1).
%Y A002820 Cf. A002884.
%Y A002820 Sequence in context: A087085 A067626 A053071 this_sequence A053290 A056989 
               A090770
%Y A002820 Adjacent sequences: A002817 A002818 A002819 this_sequence A002821 A002822 
               A002823
%K A002820 nonn,nice,easy
%O A002820 2,1
%A A002820 N. J. A. Sloane (njas(AT)research.att.com).
%E A002820 More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Mar 17 2000