

A111852


Number of numbers m <= n such that 2 equals the first digit after decimal point of square root of n in decimal representation.


11



0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 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, 6, 7, 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, 9, 10
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OFFSET

1,18


COMMENTS

For n>1: if A023961(n)=2 then a(n)=a(n1)+1 else a(n)=a(n1).
a(n)/n > 1/10.


REFERENCES

G. Polya and G. Szego, Problems and Theorems in Analysis I (Springer 1924, reprinted 1972), Part Two, Chap. 4, Sect. 4, Problem 178.


LINKS

Table of n, a(n) for n=1..105.


EXAMPLE

a(10) = 1, a(100) = 9, a(1000) = 99, a(10000) = 990.


CROSSREFS

Cf. A111850, A111851, A111853, A111854, A111855, A111856, A111857, A111858, A111859, A111892.
Sequence in context: A135662 A111853 A111851 * A133880 A226233 A059995
Adjacent sequences: A111849 A111850 A111851 * A111853 A111854 A111855


KEYWORD

nonn,base


AUTHOR

Reinhard Zumkeller, Aug 20 2005


STATUS

approved



