A032829 Numbers whose set of base-5 digits is {3,4}.

3, 4, 18, 19, 23, 24, 93, 94, 98, 99, 118, 119, 123, 124, 468, 469, 473, 474, 493, 494, 498, 499, 593, 594, 598, 599, 618, 619, 623, 624, 2343, 2344, 2348, 2349, 2368, 2369, 2373, 2374, 2468, 2469, 2473, 2474, 2493, 2494, 2498

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000
• Index entries for 5-automatic sequences.

Crossrefs

Cf. A007091.

Programs

Magma

[n: n in [1..2800] | Set(IntegerToSequence(n, 5)) subset {3, 4}];// Vincenzo Librandi, May 29 2012

Mathematica

Flatten[Table[FromDigits[#,5]&/@Tuples[{3,4},n],{n,5}]] (* Vincenzo Librandi, May 29 2012 *)

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 */

Formula

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