%I A001149 M0689 N0254
%S A001149 1,2,3,5,8,13,17,26,34,45,54,67,81,97,115,132,153,171,198,228,256,
%T A001149 288,323,357,400,439,488,530,581,627,681,732,790,843,908,963,1029,1085
%N A001149 A self-generating sequence: a(1)=1, a(2)=2, a(n+1) chosen so that a(n+1)-a(n-1) 
               is the first number not obtainable as a(j)-a(i) for 1<=i<j<=n.
%D A001149 R. K. Guy, The second strong law of small numbers. Math. Mag. 63 (1990), 
               no. 1, 3-20.
%D A001149 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A001149 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%Y A001149 Cf. A054540.
%Y A001149 Sequence in context: A078695 A121367 A070217 this_sequence A144117 A081612 
               A120761
%Y A001149 Adjacent sequences: A001146 A001147 A001148 this_sequence A001150 A001151 
               A001152
%K A001149 nonn
%O A001149 1,2
%A A001149 N. J. A. Sloane (njas(AT)research.att.com).
%E A001149 Description corrected and moved to name line by Franklin T. Adams-Watters 
               (FrankTAW(AT)Netscape.net), Nov 01 2009