%I A006446 M0548
%S A006446 1,2,3,4,6,8,9,12,15,16,20,24,25,30,35,36,42,48,49,56,63,64,72,80,81,
%T A006446 90,99,100,110,120,121,132,143,144,156,168,169,182,195,196,210,224,
%U A006446 225,240,255,256,272,288,289,306,323,324,342,360,361,380,399,400,420
%N A006446 Numbers n such that floor( sqrt n ) divides n.
%C A006446 Numbers of the form k^2, k*(k+1), or k*(k+2). Nonsquare elements of this 
               sequence are given by A035106. - Max Alekseyev (maxale(AT)gmail.com), 
               Nov 27 2006
%D A006446 T. M. Apostol, Introduction to Analytic Number Theory, Springer-Verlag, 
               1976, page 73, problem 21.
%D A006446 S. W. Golomb, Problem E2491, Amer. Math. Monthly, 82 (1975), 854-855.
%D A006446 J. O. Shallit, personal communication.
%D A006446 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%H A006446 S. Plouffe, <a href="http://www.lacim.uqam.ca/%7Eplouffe/articles/MasterThesis.pdf">
               Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures</
               a>, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 
               1992.
%H A006446 S. Plouffe, <a href="http://www.lacim.uqam.ca/%7Eplouffe/articles/FonctionsGeneratrices.pdf">
               1031 Generating Functions and Conjectures</a>, Universit\'{e} du 
               Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
%p A006446 A006446:=(-1-z-z**2+z**3)/(z**2+z+1)**2/(z-1)**3; [Conjectured by S. 
               Plouffe in his 1992 dissertation.]
%t A006446 Select[ Range[ 500 ], Mod[ #, Floor[ Sqrt[ # ]//N ] ]==0& ]
%Y A006446 Cf. A066377.
%Y A006446 Cf. A035106, A087811.
%Y A006446 Sequence in context: A122380 A033501 A097273 this_sequence A002348 A019469 
               A081491
%Y A006446 Adjacent sequences: A006443 A006444 A006445 this_sequence A006447 A006448 
               A006449
%K A006446 nonn,easy,nice
%O A006446 1,2
%A A006446 N. J. A. Sloane (njas(AT)research.att.com).