A169967 Numbers whose decimal expansion contains only 0's and 4's.

0, 4, 40, 44, 400, 404, 440, 444, 4000, 4004, 4040, 4044, 4400, 4404, 4440, 4444, 40000, 40004, 40040, 40044, 40400, 40404, 40440, 40444, 44000, 44004, 44040, 44044, 44400, 44404, 44440, 44444, 400000, 400004, 400040, 400044, 400400, 400404, 400440, 400444

Offset

1,2

Links

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

Index entries for 10-automatic sequences.

Formula

a(n+1) = Sum_{k>=0} A030308(n,k)*A093141(k+1). - Philippe Deléham, Oct 16 2011

a(n) = 4 * A007088(n-1).

Mathematica

FromDigits/@Tuples[{0, 4}, 6] (* Harvey P. Dale, Dec 21 2018 *)

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*4)))) \\ Charles R Greathouse IV, Nov 16 2011
(Haskell)
a169967 n = a169967_list !! (n-1)
a169967_list = map (* 4) a007088_list
-- Reinhard Zumkeller, Jan 10 2012

Crossrefs

Cf. A007088, A014263, A093141, A169964, A169965, A169966, A078243, A204093, A204094, A204095, A097256.

Sequence in context: A217397 A104292 A077329 * A061473 A367926 A091104

Adjacent sequences: A169964 A169965 A169966 * A169968 A169969 A169970

Keyword

nonn,base,easy

Author

N. J. A. Sloane, Aug 07 2010

Status

approved