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A152834 Numbers of form 6k+1 that use only digits 2 and 3. 3

%I

%S 223,2233,2323,3223,22333,23233,23323,32233,32323,33223,222223,223333,

%T 232333,233233,233323,322333,323233,323323,332233,332323,333223,

%U 2222233,2222323,2223223,2232223,2233333,2322223,2323333,2332333,2333233,2333323,3222223

%N Numbers of form 6k+1 that use only digits 2 and 3.

%C Equivalently, sequences of 2's and 3's, ending with 3, where the number of 2's is congruent to 2 mod 3. - Franklin T. Adams-Watters, Dec 14 2008

%H Robert Israel, <a href="/A152834/b152834.txt">Table of n, a(n) for n = 1..340</a>

%H <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>.

%p (Maple program from Robert Israel:)

%p M:= proc(n) option remember; (map(t -> 2*10^n+t,M(n-1)) union map(t ->

%p 3*10^n+t,M(n-1))) end proc;

%p M(0):= {2,3};

%p select(t -> (t mod 6 = 1), `union`(seq(M(n),n=1..9)));

%t Do[If[Union[IntegerDigits[6k+1]]=={2,3},Print[6k+1]],{k,100000}]

%t Select[Flatten[Table[FromDigits/@Tuples[{2,3},n],{n,7}]],Mod[#,6]==1&] (* _Harvey P. Dale_, Aug 02 2015 *)

%o (PARI) is(n)=n%30==13 && Set(digits(n))==[2,3] \\ _Charles R Greathouse IV_, Feb 15 2017

%Y Subsequence of A152824.

%K nonn,base,easy

%O 1,1

%A _Zak Seidov_, Dec 14 2008

%E Extended by Robert Israel, Dec 14 2008

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Last modified April 19 05:00 EDT 2021. Contains 343105 sequences. (Running on oeis4.)