A070843 - OEIS

%I #13 Sep 30 2021 13:17:44

%S 9,99,996,9996,99990,999570,9999990,99981420,999068070,9592993410

%N Largest n-digit number with exactly n distinct prime divisors. There are no further terms.

%C Primes counted without multiplicity. - _Harvey P. Dale_, Sep 30 2021

%e a(4) = 9996 with the prime divisors 2,3,7 and 17.

%t Do[k = 10^n - 1; While[Length[FactorInteger[k]] != n, k-- ]; Print[k], {n, 1, 10}] (* _Ryan Propper_, Nov 05 2005 *)

%t lnpd[n_]:=Module[{k=10^n-1},While[PrimeNu[k]!=n,k--];k]; Array[lnpd,10] (* _Harvey P. Dale_, Sep 30 2021 *)

%Y Cf. A070842.

%K base,nonn,fini,full

%O 1,1

%A _Amarnath Murthy_, May 12 2002

%E More terms from _Rick L. Shepherd_, May 14 2002

%E a(10) from _Ryan Propper_, Nov 05 2005

%E Edited by _Ray Chandler_, Feb 15 2009

%E Definition clarified by _Harvey P. Dale_, Sep 30 2021