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 A169967 Numbers whose decimal expansion contains only 0's and 4's. 14
 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 (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)*A093141(k+1)}. - From 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: A104292 A131535 A077329 * A061473 A091104 A069539 Adjacent sequences:  A169964 A169965 A169966 * A169968 A169969 A169970 KEYWORD nonn,base,easy AUTHOR N. J. A. Sloane, Aug 07 2010 STATUS approved

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Last modified January 23 17:13 EST 2019. Contains 319399 sequences. (Running on oeis4.)