%I #16 Feb 12 2017 17:28:51
%S 12,15,18,21,51,81,102,105,108,111,114,117,120,123,126,129,132,135,
%T 138,141,144,147,150,153,156,159,162,165,168,171,174,177,180,183,186,
%U 189,192,195,198,201,210,213,216,219,231,261,291,312,315,318,321,351,381,411,414
%N Positive multiples of 3 that contain the decimal digit 1.
%C I came across this sequence while working some problems in ALCUMUS from the AoPS site. [Tyler]
%C A 10-automatic set: members are numbers with decimal expansions matching a regular expression. - _Charles R Greathouse IV_, Feb 20 2012
%D MathCounts 2006 National Target #5
%H <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>.
%t Select[3*Range[138], DigitCount[#, 10, 1] > 0 &] (* _Alonso del Arte_, Feb 20 2012 *)
%o (PARI) is(n)=if(n%3,return(0));n=vecsort(eval(Vec(Str(n))),,8);n[1]==1||(#n>1&&n[2]==1) \\ _Charles R Greathouse IV_, Feb 20 2012
%o (PARI) is(n)=n%3==0 && setsearch(Set(digits(n)), 1) \\ _Charles R Greathouse IV_, Feb 12 2017
%K nonn,base,easy
%O 1,1
%A _Seth Tyler_, Feb 20 2012
%E a(7)-a(55) from _Charles R Greathouse IV_, Feb 20 2012