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

1,2

Links

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

Formula

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

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

Mathematica

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

Prog

(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
(Haskell)
a169966 n = a169966_list !! (n-1)
a169966_list = map (* 3) a007088_list
-- Reinhard Zumkeller, Jan 10 2012
(Python)
def a(n): return 3*int(bin(n)[2:])
print([a(n) for n in range(40)]) # Michael S. Branicky, Mar 30 2021

Crossrefs

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

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

Sequence in context: A121023 A124520 A350814 * A140153 A095045 A061472

Adjacent sequences: A169963 A169964 A169965 * A169967 A169968 A169969

Keyword

nonn,base,easy

Author

N. J. A. Sloane, Aug 07 2010

Status

approved