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 A169964 Numbers whose decimal expansion contains only 0's and 5's. 14
 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 (list; graph; refs; listen; history; text; internal format)
 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)*A093143(k+1)}. - From Philippe Deléham, Oct 16 2011. a(n) = 5 * A007088(n-1). 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

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Last modified August 24 03:51 EDT 2019. Contains 326260 sequences. (Running on oeis4.)