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!)
A071811 Sum_{k <= 10^n} number of primes (counted with multiplicity) dividing k (A001222). 0
0, 15, 239, 2877, 31985, 343614, 3626619, 37861249, 392351272, 4044220058, 41518796555, 424904645958, 4337589196099, 44189168275565, 449411845856902, 4564053529871328, 46294122513328879, 469075734968975581, 4748553675150670580, 47797839092868715542 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Also bigomega( (10^n)! ), where bigomega(x): number of prime divisors of x, counted with multiplicity. - Cino Hilliard, Jul 04 2007

LINKS

Table of n, a(n) for n=0..19.

EXAMPLE

a(1)=15 because bigomega(1) + bigomega(2) + ... + bigomega(10) = 0+1+1+2+1+2+1+3+2+2 = 15.

MATHEMATICA

With[{s = Array[PrimeOmega, 10^6]}, {0}~Join~Array[Total@ Take[s, 10^#] &, Floor@ Log10@ Length@ s]] (* Michael De Vlieger, Dec 17 2017 *)

PROG

(PARI) s=0; n=0; for(k=1, 10^8, s=s+bigomega(k); if(k==10^n, print1(s, ", "); n++))

(PARI) g(n) = for(x=0, n, print1(bigomega((10^x)!), ", ")) \\ Cino Hilliard, Jul 04 2007

CROSSREFS

Cf. A001222 (bigomega), A064182 (corresponding sums for distinct primes).

Sequence in context: A057007 A209118 A093745 * A157456 A343527 A097262

Adjacent sequences:  A071808 A071809 A071810 * A071812 A071813 A071814

KEYWORD

nonn

AUTHOR

Rick L. Shepherd, Jun 07 2002

EXTENSIONS

a(9) from Charles R Greathouse IV, Dec 11 2008

a(11)-a(12) from Giovanni Resta, Oct 26 2012

a(13)-a(17) from Hiroaki Yamanouchi, Aug 28 2014

a(18)-a(19) from Henri Lifchitz, Dec 17 2017

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 November 28 13:47 EST 2021. Contains 349413 sequences. (Running on oeis4.)