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
FORMULA
From Amiram Eldar, Oct 11 2024: (Start)
a(n) = A022559(10^n).
a(n) ~ 10^n * (log(log(10^n)) + B_2), where B_2 = A083342. (End)
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
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