A032829 - OEIS

%I #20 Sep 08 2022 08:44:51

%S 3,4,18,19,23,24,93,94,98,99,118,119,123,124,468,469,473,474,493,494,

%T 498,499,593,594,598,599,618,619,623,624,2343,2344,2348,2349,2368,

%U 2369,2373,2374,2468,2469,2473,2474,2493,2494,2498

%N Numbers whose set of base-5 digits is {3,4}.

%H Vincenzo Librandi, <a href="/A032829/b032829.txt">Table of n, a(n) for n = 1..1000</a>

%H <a href="/index/Ar#5-automatic">Index entries for 5-automatic sequences</a>.

%F a(1)=3, a(2)=4; a(n) = 5*a(floor(n/2))+3 for n odd, otherwise a(n) = 5*a(floor((n-1)/2))+4. - _Bruno Berselli_, May 30 2012

%t Flatten[Table[FromDigits[#,5]&/@Tuples[{3,4},n],{n,5}]] (* _Vincenzo Librandi_, May 29 2012 *)

%o (Magma) [n: n in [1..2800] | Set(IntegerToSequence(n, 5)) subset {3, 4}];// _Vincenzo Librandi_, May 29 2012

%o (Maxima) a[1]:3$ a[2]:4$ a[n]:= if oddp(n) then 5*a[floor(n/2)]+3 else 5*a[floor((n-1)/2)]+4$ makelist(a[n],n,1,45); /* _Bruno Berselli_, May 30 2012 */

%Y Cf. A007091.

%K nonn,base,easy

%O 1,1

%A _Clark Kimberling_