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 A001637 Numbers with an even number of digits. 8
 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 1000, 1001 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The lower and upper asymptotic densities of this sequence are 1/11 and 10/11, respectively. - Amiram Eldar, Feb 01 2021 LINKS T. D. Noe, Table of n, a(n) for n = 1..1000 FORMULA A055642(a(n)) mod 2 = 0. - Reinhard Zumkeller, Jul 14 2014 MATHEMATICA Select[Range[0, 1001], EvenQ[Length[IntegerDigits[#]]] &] (* T. D. Noe, Aug 09 2012 *) PROG (Haskell) a001637 n = a001637_list !! (n-1) a001637_list = filter (even . a055642) [0..] -- Reinhard Zumkeller, Jul 14 2014 (PARI) is(n)=#Str(n)%2==0 \\ Charles R Greathouse IV, Nov 26 2018 CROSSREFS Cf. A001633 (complement), A055642. Sequence in context: A088475 A171891 A328075 * A308407 A102494 A117884 Adjacent sequences:  A001634 A001635 A001636 * A001638 A001639 A001640 KEYWORD nonn,base,easy AUTHOR STATUS approved

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Last modified April 20 06:59 EDT 2021. Contains 343125 sequences. (Running on oeis4.)