%I A141837
%S A141837 13,31,133,120332323
%N A141837 a(n) = first term that can be reduced in n steps via repeated interpretation 
               of a(n) as a base b+1 number where b is the largest digit of a(n), 
               such that b is always 3 so that each interpretation is base 4. Terms 
               already fully reduced (i.e. single digits) are excluded.
%C A141837 It is possible to compute additional terms by taking the last term, treating 
               it as base-10 and converting to base-4. This will necessarily create 
               a term which can converted back to base 10 yielding the previous 
               term in the sequence which will itself yield N further terms. But 
               there is no guarantee (except in base 2) that the term so derived 
               will be the first term to produce a sequence of N+1 terms. There 
               could be another, smaller, term which satisfies that requirement 
               but which uses different terms. Pushing the last term of this sequence 
               yields 13023002000203 as a possible next term.
%e A141837 a(3) = 133 because 133 is the first number that can produce a sequence 
               of three terms by repeated interpetation as a base 4 number: [133] 
               (base-4) --> [31] (base-4) --> [13] (base-4) --> [7]. Since 7 cannot 
               be interpretted as a base 4 number, the sequence terminates with 
               13. a(1) = 13 because 13 is the first number that can be reduced 
               once, yielding no further terms interprettable as base 4.
%Y A141837 Cf. A091049, A141836, A141838, A141839, A141840, A141841, A141842.
%Y A141837 Sequence in context: A043226 A044006 A007628 this_sequence A104151 A023304 
               A159670
%Y A141837 Adjacent sequences: A141834 A141835 A141836 this_sequence A141838 A141839 
               A141840
%K A141837 base,more,nonn
%O A141837 1,1
%A A141837 Chuck Seggelin (seqfan(AT)plastereddragon.com), Jul 10 2008