A169966 Numbers whose decimal expansion contains only 0's and 3's.

0, 3, 30, 33, 300, 303, 330, 333, 3000, 3003, 3030, 3033, 3300, 3303, 3330, 3333, 30000, 30003, 30030, 30033, 30300, 30303, 30330, 30333, 33000, 33003, 33030, 33033, 33300, 33303, 33330, 33333, 300000, 300003, 300030, 300033, 300300, 300303, 300330, 300333

Offset: 1

Author

N. J. A. Sloane, Aug 07 2010

Keywords

• nonn
• base
• easy

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A007088, A014263, A169964, A169965, A169967.

Cf. A078242, A204093, A204094, A204095, A097256.

Programs

Haskell

a169966 n = a169966_list !! (n-1)
a169966_list = map (* 3) a007088_list
-- Reinhard Zumkeller, Jan 10 2012

Mathematica

Map[FromDigits,Tuples[{0,3},6]] (* Paolo Xausa, Oct 30 2023 *)

PARI

print1(0);for(d=1,5,for(n=2^(d-1),2^d-1,print1(", ");forstep(i=d-1,0,-1,print1((n>>i)%2*3)))) \\ Charles R Greathouse IV, Nov 16 2011

Python

def a(n): return 3*int(bin(n)[2:])
print([a(n) for n in range(40)]) # Michael S. Branicky, Mar 30 2021

Formula

a(n+1) = Sum_{k>=0} A030308(n,k)*A093138(k+1). - Philippe Deléham, Oct 16 2011

a(n) = 3 * A007088(n-1).