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 A180927 #15 Jan 27 2021 05:30:50
%S A180927 8,99,994,9994,99997,999994,9999994,99999994,999999998,9999999995,
%T A180927 99999999998,999999999998,9999999999998,99999999999998,
%U A180927 999999999999995,9999999999999998,99999999999999998,999999999999999987,9999999999999999999
%N A180927 Largest n-digit number that is divisible by exactly 3 primes (counted with multiplicity).
%C A180927 This is to 3 and A014612, as 2 and A098450 (largest n-digit semiprime), and as 1 and A003618 (largest n-digit prime). Largest n-digit triprime. Largest n-digit 3-almost prime.
%e A180927 a(1) = 8 because 8 = 2^3 is the largest (only) 1-digit number that is divisible by exactly 3 primes (counted with multiplicity).
%e A180927 a(2) = 99 because 99 = 3^2 * 11 is the largest 2-digit number (of 21) that is divisible by exactly 3 primes (counted with multiplicity).
%e A180927 a(3) = 994 because 994 = 2 * 7 * 71 is the largest 3-digit number that is divisible by exactly 3 primes (counted with multiplicity).
%t A180927 lndn3[n_]:=Module[{k=10^n-1},While[PrimeOmega[k]!=3,k--];k]; Array[ lndn3,20] (* _Harvey P. Dale_, Jul 25 2019 *)
%o A180927 (PARI) A180927(n)=forstep(n=10^n-1,10^(n-1),-1,bigomega(n)==3&return(n)) \\ _M. F. Hasler_, Jan 23 2011
%Y A180927 Cf. A003618, A014612, A098450, A180922.
%K A180927 nonn,base,easy
%O A180927 1,1
%A A180927 _Jonathan Vos Post_, Jan 23 2011