login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A322416 The number of exponentially odd numbers <= 10^n. 0
1, 8, 70, 707, 7055, 70457, 704464, 7044494, 70444319, 704442438 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..9.

Eckford Cohen, Arithmetical functions associated with the unitary divisors of an integer, Mathematische Zeitschrift, Vol. 74, Vol. 1 (1960), pp. 66-80.

Aleksandar Ivic, A convolution theorem with applications to some divisor functions, Publications de l'Institut Mathématique, Vol. 24, No. 38 (1978), pp. 67-78.

D. Suryanarayana and R. Sita Rama Chandra Rao, Distribution of unitarily k-free integers, Journal of the Australian Mathematical Society, Vol. 20, No. 2 (1975), pp. 129-141.

FORMULA

Lim_{n->oo} a(n)/10^n = 0.704442... (A065463).

MATHEMATICA

c=0; n=0; s={}; Do[If[k > 10^n, AppendTo[s, c]; n++]; If[AllTrue[Last /@ FactorInteger[k], OddQ], c++], {k, 1, 10^6}]; s

CROSSREFS

Cf. A065463, A268335.

Sequence in context: A152263 A142986 A123511 * A287482 A053729 A266433

Adjacent sequences:  A322413 A322414 A322415 * A322417 A322418 A322419

KEYWORD

nonn,more

AUTHOR

Amiram Eldar, Aug 28 2019

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 22 02:50 EDT 2020. Contains 337289 sequences. (Running on oeis4.)