%I A007448 M2276
%S A007448 1,3,3,4,7,7,7,9,9,10,13,13,13,15,15,19,19,19,19,21,21,22,27,27,27,
%T A007448 27,27,28,31,31,31,39,39,39,39,39,39,39,39,40,43,43,43,45,45,46,55,55,
%U A007448 55,55,55,55,55,55,55,57,57,58,63,63,63,63,63,64,67,67,67,79,79,79,79
%N A007448 Knuth's sequence (or Knuth numbers): a(n+1) = 1 + min ( 2 a[ n/2 ], 3 
               a[ n/3 ] ).
%D A007448 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A007448 R. L. Graham, D. E. Knuth and O. Patashnik, Concrete Mathematics. Addison-Wesley, 
               Reading, MA, 1990, p. 78.
%H A007448 T. D. Noe, <a href="b007448.txt">Table of n, a(n) for n=0..1000</a>
%H A007448 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               KnuthNumber.html">Link to a section of The World of Mathematics.</
               a>
%t A007448 a[1] = 1; a[n_] := a[n] = 1 + Min[ 2a[Ceiling[(n - 1)/2]], 3a[Ceiling[(n 
               - 1)/3]]]; Table[ a[n], {n, 72}] (from Robert G. Wilson v Jan 29 
               2005)
%Y A007448 Cf. A002977.
%Y A007448 Sequence in context: A058660 A059871 A076619 this_sequence A155689 A051263 
               A058674
%Y A007448 Adjacent sequences: A007445 A007446 A007447 this_sequence A007449 A007450 
               A007451
%K A007448 easy,nonn,nice
%O A007448 0,2
%A A007448 N. J. A. Sloane (njas(AT)research.att.com).