%I A011260 M0107 N0132
%S A011260 1,1,2,2,6,6,18,16,48,60,176,144,630,756,1800,2048,7710,
%T A011260 7776,27594,24000,84672,120032,356960,276480,1296000,1719900,
%U A011260 4202496,4741632,18407808,17820000,69273666,67108864,211016256
%N A011260 Number of primitive polynomials of degree n over GF(2).
%D A011260 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A011260 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A011260 E. R. Berlekamp, Algebraic Coding Theory, McGraw-Hill, NY, 1968, p. 84.
%D A011260 T. L. Booth, An analytical representation of signals in sequential networks, 
               pp. 301-3240 of Proceedings of the Symposium on Mathematical Theory 
               of Automata. New York, N.Y., 1962. Microwave Research Institute Symposia 
               Series, Vol. XII; Polytechnic Press of Polytechnic Inst. of Brooklyn, 
               Brooklyn, N.Y. 1963 xix+640 pp. See p. 303.
%D A011260 R. Church, Tables of irreducible polynomials for the first four prime 
               moduli, Annals Math., 36 (1935), 198-209.
%D A011260 P. Fan and M. Darnell, Sequence Design for Communications Applications, 
               Wiley, NY, 1996, Table 5.1, p. 118.
%D A011260 W. W. Peterson and E. J. Weldon, Jr., Error-Correcting Codes. MIT Press, 
               Cambridge, MA, 2nd edition, 1972, p. 476.
%D A011260 M. P. Ristenblatt, Pseudo-Random Binary Coded Waveforms, pp. 274-314 
               of R. S. Berkowitz, editor, Modern Radar, Wiley, NY, 1965; see p. 
               296.
%H A011260 David W. Wilson, <a href="b011260.txt">Table of n, a(n) for n=1..400</
               a>
%H A011260 Joerg Arndt, <a href="http://www.jjj.de/fxt/#fxtbook">Fxtbook</a>
%H A011260 P. Koopman, <a href="http://www.cs.cmu.edu/~koopman/lfsr/index.html">
               Complete lists up to N=32</a>
%H A011260 F. Ruskey, <a href="http://www.theory.cs.uvic.ca/~cos/inf/neck/PolyInfo.html">
               Primitive and Irreducible Polynomials</a>
%H A011260 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               PrimitivePolynomial.html">Link to a section of The World of Mathematics.</
               a>
%p A011260 with(numtheory): phi(2^n-1)/n;
%t A011260 Table[EulerPhi[(2^n - 1)]/n, {n, 1, 50}]
%o A011260 (PARI) a(n)=eulerphi(2^n-1)/n - Hauke Worpel (thebigh(AT)outgun.com), 
               Jun 10 2008
%Y A011260 See A058947 for initial terms. Cf. A001037, A000020.
%Y A011260 Cf. A027695.
%Y A011260 Sequence in context: A034422 A140833 A071908 this_sequence A117855 A086442 
               A071407
%Y A011260 Adjacent sequences: A011257 A011258 A011259 this_sequence A011261 A011262 
               A011263
%K A011260 nonn,easy,nice
%O A011260 1,3
%A A011260 N. J. A. Sloane (njas(AT)research.att.com).