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Search: id:A101640
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| A101640 |
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Positive integers n for which n = f(n), where f(n) is the total number of 3's required when writing out all numbers between 0 and n. |
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10
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| 371599983, 371599984, 371599985, 371599986, 371599987, 371599988, 371599989, 371599990, 371599991, 371599992, 500000000, 10000000000, 10371599983, 10371599984, 10371599985, 10371599986, 10371599987, 10371599988
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Related to a problem posed by Google and discussed on the MathWorld link.
Together with the b-file, this gives the complete list of all 35 positive numbers n such that n is equal to the number of 3's in the decimal digits of all numbers <= n. - Daniel Hirschberg (dan(AT)ics.uci.edu), May 05 2007
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LINKS
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Daniel Hirschberg (dan(AT)ics.uci.edu), May 05 2007, Table of n, a(n) for n = 1..35
Mathworld, A problem posed by Google
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EXAMPLE
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a(1) = 371599983, since writing out all numbers from 0 to 371599983 requires that 371599983 3's be used and since 371599983 is the first such positive integer.
a(4)=371599986 because the number of 3's in the decimal digits of the numbers from 1 to 371599986 is 371599986, and this is the 4th such number.
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CROSSREFS
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Cf. A014778 for proof these sequences are finite; Also A101639, A101641, A130427, A130428, A130429, A130430, A130431; cf. A130432 for the number of numbers in these sequences.
Sequence in context: A017471 A017603 A112445 this_sequence A129248 A144768 A057071
Adjacent sequences: A101637 A101638 A101639 this_sequence A101641 A101642 A101643
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KEYWORD
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base,fini,nonn
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AUTHOR
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Ryan Propper (rpropper(AT)stanford.edu), Dec 10 2004
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EXTENSIONS
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More terms from Daniel Hirschberg (dan(AT)ics.uci.edu), May 05 2007
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