login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A106598 Number of positive integers <= 10^n that are divisible by no prime exceeding 5. 6

%I #10 Sep 05 2020 20:37:47

%S 1,9,34,86,175,313,507,768,1105,1530,2053,2683,3429,4301,5310,6466,

%T 7780,9259,10917,12761,14801,17048,19511,22201,25127,28300,31730,

%U 35425,39397,43654,48207,53066,58243,63746,69584,75769,82310,89216,96499,104168

%N Number of positive integers <= 10^n that are divisible by no prime exceeding 5.

%H David A. Corneth, <a href="/A106598/b106598.txt">Table of n, a(n) for n = 0..1500</a>

%t n = 40; t = Select[ Flatten[ Table[ 5^c*Select[ Flatten[ Table[2^a*3^b, {a, 0, n*Log[2, 10]}, {b, 0, n*Log[3, 10]}]], # <= 10^n &], {c, 0, n*Log[5, 10]}]], # <= 10^n &]; Table[ Length[ Select[t, # <= 10^n &]], {n, 0, 40}]

%Y Row 3 of A253635.

%Y Cf. A011557, A051037, A071520.

%K nonn

%O 0,2

%A _Robert G. Wilson v_, May 27 2005

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 25 01:35 EDT 2024. Contains 371964 sequences. (Running on oeis4.)