login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A168048 C(n)*Pi(n), C(n) = number of nonprimes <=n, Pi(n)= number of primes <=n; n = 2,3,4,5,...A000720*A062298 1
0, 1, 2, 4, 6, 9, 12, 16, 20, 24, 30, 35, 42, 48, 54, 60, 70, 77, 88, 96, 104, 112, 126, 135, 144, 153, 162, 171, 190, 200, 220, 231, 242, 253, 264, 275, 300, 312, 324, 336, 364, 377, 406, 420, 434, 448, 480, 495, 510, 525, 540, 555, 592, 608, 624, 640, 656, 672 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..58.

MAPLE

A000720 := proc(n) numtheory[pi](n) ; end proc: A168048 := proc(n) pi := A000720(n) ; pi*(n-pi) ; end proc: seq(A168048(n), n=1..120) ; [From R. J. Mathar, Nov 18 2009]

CROSSREFS

Cf. A000720, A062298

Sequence in context: A095114 A062048 A194174 * A075354 A194164 A194254

Adjacent sequences:  A168045 A168046 A168047 * A168049 A168050 A168051

KEYWORD

nonn

AUTHOR

Daniel Tisdale, Nov 17 2009

EXTENSIONS

a(1) and terms after a(16) from R. J. Mathar, Nov 18 2009

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 17 19:36 EDT 2018. Contains 316293 sequences. (Running on oeis4.)