A111890 Number of numbers m <= n such that 0 equals the second digit after decimal point of square root of n in decimal representation.

1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14

Offset

1,4

Comments

For n > 1: if A111862(n)=4 then a(n) = a(n-1) + 1, otherwise a(n) = a(n-1).

Lim_{n->infinity} a(n)/n = 1/10.

References

G. Pólya and G. Szegő, 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..86.

Example

a(10) = 3, a(100) = 15, a(1000) = 104, a(10000) = 1006.

Crossrefs

Cf. A111891, A111892, A111893, A111894, A111895, A111896, A111897, A111898, A111899, A111850.

Sequence in context: A218085 A290726 A090663 * A104277 A125893 A005857

Adjacent sequences: A111887 A111888 A111889 * A111891 A111892 A111893

Keyword

nonn,base

Author

Reinhard Zumkeller, Aug 20 2005

Status

approved