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A175843 a(n) = (10^n)-th odd squarefree number. 0
1, 21, 241, 2463, 24671, 246745, 2467401, 24674017, 246740209, 2467401073, 24674011069, 246740110021, 2467401100859, 24674011004865, 246740110026451, 2467401100272455, 24674011002722867, 246740110027242491, 2467401100272345957 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..18.

FORMULA

a(n) ~ (pi/2)^2 * 10^n + O(10^(n/2)). This follows from the formula given in A056911: A056911(n) ~ n * (3/2) * zeta(2) + O(n^(1/2)) = n * (3/2) * (pi^2 / 6) + O(n^(1/2)). - M. F. Hasler

CROSSREFS

Cf. A056911.

Sequence in context: A069601 A173347 A089937 * A198974 A271792 A177730

Adjacent sequences:  A175840 A175841 A175842 * A175844 A175845 A175846

KEYWORD

nonn

AUTHOR

Zak Seidov, Sep 24 2010

EXTENSIONS

a(10)-a(18) from Max Alekseyev, Sep 24 2010

Edited by N. J. A. Sloane, Sep 24 2010

STATUS

approved

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Last modified March 30 20:18 EDT 2017. Contains 284302 sequences.