%I A147991
%S A147991 1,2,4,5,7,11,13,14,16,20,22,32,34,38,40,41,43,47,49,59,61,65,67,95,96,
%T A147991 101,103,113,115,119,121,122,124,128,130,140,142,146,148,176,178,182,
%U A147991 184,194,196,200,202,284,286,290,292,302,304,308,310,338,340,344,346
%N A147991 Sequence S such that 1 is in S and if x is in S, then 3x-1 and 3x+1 are 
               in S.
%e A147991 0th generation: 1
%e A147991 1st generation: 2 4
%e A147991 2nd generation: 5 7 11 13
%Y A147991 Sequence in context: A108464 A128815 A056527 this_sequence A033160 A110924 
               A028289
%Y A147991 Adjacent sequences: A147988 A147989 A147990 this_sequence A147992 A147993 
               A147994
%K A147991 nonn
%O A147991 1,2
%A A147991 Clark Kimberling (ck6(AT)evansville.edu), Dec 07 2008