This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A071811 #31 Oct 12 2024 03:54:41
%S A071811 0,15,239,2877,31985,343614,3626619,37861249,392351272,4044220058,
%T A071811 41518796555,424904645958,4337589196099,44189168275565,
%U A071811 449411845856902,4564053529871328,46294122513328879,469075734968975581,4748553675150670580,47797839092868715542
%N A071811 a(n) = Sum_{k = 1..10^n} number of primes (counted with multiplicity) dividing k (A001222).
%C A071811 Also bigomega( (10^n)! ), where bigomega(x): number of prime divisors of x, counted with multiplicity. - _Cino Hilliard_, Jul 04 2007
%F A071811 From _Amiram Eldar_, Oct 11 2024: (Start)
%F A071811 a(n) = A022559(10^n).
%F A071811 a(n) ~ 10^n * (log(log(10^n)) + B_2), where B_2 = A083342. (End)
%e A071811 a(1) = 15 because bigomega(1) + bigomega(2) + ... + bigomega(10) = 0+1+1+2+1+2+1+3+2+2 = 15.
%t A071811 With[{s = Array[PrimeOmega, 10^6]}, {0}~Join~Array[Total@ Take[s, 10^#] &, Floor@ Log10@ Length@ s]] (* _Michael De Vlieger_, Dec 17 2017 *)
%o A071811 (PARI) s=0; n=0; for(k=1,10^8, s=s+bigomega(k); if(k==10^n,print1(s,","); n++))
%o A071811 (PARI) g(n) = for(x=0,n,print1(bigomega((10^x)!),",")) \\ _Cino Hilliard_, Jul 04 2007
%Y A071811 Cf. A001222 (bigomega), A022559, A064182 (corresponding sums for distinct primes), A083342.
%K A071811 nonn
%O A071811 0,2
%A A071811 _Rick L. Shepherd_, Jun 07 2002
%E A071811 a(9) from _Charles R Greathouse IV_, Dec 11 2008
%E A071811 a(11)-a(12) from _Giovanni Resta_, Oct 26 2012
%E A071811 a(13)-a(17) from _Hiroaki Yamanouchi_, Aug 28 2014
%E A071811 a(18)-a(19) from _Henri Lifchitz_, Dec 17 2017