%I A072235
%S A072235 240,164,87,12,66,141,218,295,374,451,530,607,684,760,837,912,989,1066,
%T A072235 1145,1222,1301,1378,1456,1531,1607,1682,1759,1835,1910,1986
%V A072235 -240,-164,-87,-12,66,141,218,295,374,451,530,607,684,760,837,912,989,
               1066,
%W A072235 1145,1222,1301,1378,1456,1531,1607,1682,1759,1835,1910,1986
%N A072235 Years of recorded observations of Comet Halley.
%C A072235 This sequence is not well-defined for many reasons (negative years are 
               ill-defined; calendars change often, so when does a year begin?; 
               what does "observed" mean?; what if the comet was observed both at 
               the end of one year and at the beginning of another, as in 1985/1986?; 
               etc.). - N. J. A. Sloane (njas(AT)research.att.com), Jun 24 2007
%C A072235 The first four terms given are years B.C., others are A.D. I do not know 
               if these years necessarily coincide with actual years of perihelion. 
               Some sources and these numbers indicate that the comet's period varies. 
               These years are taken directly from the U.S. National Air and Space 
               Museum link.
%H A072235 National Air and Space Museum, <a href="http://www.nasm.si.edu/ceps/etp/
               comets/comet_history.html">Exploring Comets - Historical Records</
               a>
%H A072235 N.A.S.A., <a href="http://nssdc.gsfc.nasa.gov/planetary/factsheet/cometfact.html">
               Comet Fact Sheet</a>
%H A072235 Wikipedia, <a href="http://www.wikipedia.org/wiki/Comet+Halley">Comet 
               Halley</a>
%Y A072235 See A100748 for another version.
%Y A072235 Sequence in context: A015161 A078151 A100748 this_sequence A121378 A135194 
               A031173
%Y A072235 Adjacent sequences: A072232 A072233 A072234 this_sequence A072236 A072237 
               A072238
%K A072235 sign
%O A072235 1,1
%A A072235 Rick L. Shepherd (rshepherd2(AT)hotmail.com), Jul 05 2002