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Search: id:A014778
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| A014778 |
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List of numbers n such that n is equal to the number of 1's in the decimal digits of all numbers <= n. |
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+0 24
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| 0, 1, 199981, 199982, 199983, 199984, 199985, 199986, 199987, 199988, 199989, 199990, 200000, 200001, 1599981, 1599982, 1599983, 1599984, 1599985, 1599986, 1599987, 1599988, 1599989, 1599990, 2600000, 2600001, 13199998, 35000000
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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The full list of 84 terms is given in the b-file.
It can be proved that this sequence is finite. (The main idea of the proof is that the number of 1's used in positive integers <= n is greater than or equal to A(n) = (1/10) number of digits in positive integers from 1 to n = (1/10) Sum_{i=1,...n} (1+Floor(log_10 i)). By considering the area below a logarithmic function and the corresponding integral, it can be shown that A(n)/n goes to infinity.) - Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Nov 05 2002
Fixed points of A094798. Sequence consists of six runs of ten consecutive numbers, ten pairs of consecutive numbers, and four isolated numbers. - David Wasserman (dwasserm(AT)earthlink.net), Jun 29 2007
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REFERENCES
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Maurice Protat "Des Olympiades a` l'Agr'egation", Editions Ellipses, Paris 1997, p. 183.
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LINKS
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Graeme McRae (g_m(AT)mcraefamily.com), May 26 2007, Table of n, a(n) for n = 1..84
Pegg, E. Jr. and Weisstein, E. W. Mathematica's Google Aptitude. MathWorld Headline news, Oct 13, 2004.
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EXAMPLE
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a(5)=199983 because the number of 1's in the decimal digits of the numbers from 0 to 199983 is 199983, and this is the 5th such number.
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CROSSREFS
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Cf. A101639, A101640, A101641, A130427, A130428, A130429, A130430, A130431; Cf. A130432 for the number of numbers in these sequences.
Cf. A094798.
Adjacent sequences: A014775 A014776 A014777 this_sequence A014779 A014780 A014781
Sequence in context: A099818 A043592 A126558 this_sequence A094799 A106777 A094800
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KEYWORD
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base,fini,nonn,full
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AUTHOR
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Yves Babe, Maurice Protat, Olivier Gerard (olivier.gerard(AT)gmail.com)
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EXTENSIONS
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Corrected and extended by Deepan Majmudar (deepan.majmudar(AT)hp.com), Nov 19 2004
41 further terms from Ryan Propper (rpropper(AT)stanford.edu), Dec 07 2004, who observed that there are no more terms <= 10^9.
The final (84-th) term 1111111110 was sent by Lambrecht Kok (L.P.Kok(at)rug.nl), Jan 13, 2005. He says: "H. van Haeringen and I showed that this list of 84 terms is complete on Dec 15 2004".
Independently shown to be complete by Ryan Propper and Vaughan Pratt, Jan 08 2005
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