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!)
A065894 Number of composites <= 10^n. 4
0, 5, 74, 831, 8770, 90407, 921501, 9335420, 94238544, 949152465, 9544947488, 95881945186, 962392087981, 9653934463160, 96795058249197, 970155429577330, 9720761658966074, 97376442842345766, 975260045712259139, 9765942332723655392, 97779180397439081159 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Also, the order number of 10^n as a composite number.

LINKS

Table of n, a(n) for n=0..20.

FORMULA

a(n) = 10^n - 1 - A006880(n). - Max Alekseyev, Aug 15 2013

For n>0, a(n) = A092871(n) + 1.

EXAMPLE

10 is the 5th composite number: 4,6,8,9,10.

MATHEMATICA

Table[ 10^n- (PrimePi[10^n]) -1, {n, 1, 13} ]

CROSSREFS

Cf. A002808.

Sequence in context: A092826 A334258 A322446 * A233013 A126740 A251666

Adjacent sequences:  A065891 A065892 A065893 * A065895 A065896 A065897

KEYWORD

nonn

AUTHOR

Labos Elemer, Nov 28 2001

EXTENSIONS

More terms from Robert G. Wilson v, Nov 29 2001

Formula and more terms from Max Alekseyev, Aug 15 2013

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 July 2 09:21 EDT 2020. Contains 335398 sequences. (Running on oeis4.)