A169964 Numbers whose decimal expansion contains only 0's and 5's.

0, 5, 50, 55, 500, 505, 550, 555, 5000, 5005, 5050, 5055, 5500, 5505, 5550, 5555, 50000, 50005, 50050, 50055, 50500, 50505, 50550, 50555, 55000, 55005, 55050, 55055, 55500, 55505, 55550, 55555, 500000, 500005, 500050, 500055, 500500, 500505, 500550, 500555

Offset

1,2

Links

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

Index entries for sequences related to carryless arithmetic

Formula

a(n+1) = Sum_{k>=0} A030308(n,k)*A093143(k+1). - Philippe Deléham, Oct 16 2011

a(n) = 5 * A007088(n-1).

Mathematica

Map[FromDigits, Tuples[{0, 5}, 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*5)))) \\ Charles R Greathouse IV, Nov 16 2011
(Haskell)
a169964 n = a169964_list !! (n-1)
a169964_list = map (* 5) a007088_list
-- Reinhard Zumkeller, Jan 10 2012

Crossrefs

Cf. A007088, A014263, A169965, A169966, A169967.

Cf. A078244, A204093, A204094, A204095, A097256.

Sequence in context: A136890 A136889 A136887 * A061474 A136916 A204193

Adjacent sequences: A169961 A169962 A169963 * A169965 A169966 A169967

Keyword

nonn,base,easy

Author

N. J. A. Sloane, Aug 07 2010

Status

approved