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A111857
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Number of numbers m <= n such that 7 equals the first digit after decimal point of square root of n in decimal representation.
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11
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0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 11, 11, 11, 11, 11, 11
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,14
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COMMENTS
| For n>1: if A023961(n)=7 then a(n)=a(n-1)+1 else a(n)=a(n-1).
a(n)/n --> 1/10.
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REFERENCES
| G. Polya and G. Szego, Problems and Theorems in Analysis I (Springer 1924, reprinted 1972), Part Two, Chap. 4, Sect. 4, Problem 178.
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EXAMPLE
| a(10) = 1, a(100) = 11, a(1000) = 99, a(10000) = 1010.
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CROSSREFS
| Cf. A111850, A111851, A111852, A111853, A111854, A111855, A111856, A111858, A111859, A111897.
Sequence in context: A171622 A111858 A111856 * A133879 A054898 A167383
Adjacent sequences: A111854 A111855 A111856 * A111858 A111859 A111860
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KEYWORD
| nonn,base
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Aug 20 2005
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