login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Smallest number of the form 10^k +1 with n distinct prime divisors.
1

%I #7 Dec 05 2013 19:56:20

%S 2,10001,1001,100000000001,1000000001,

%T 1000000000000000000000000000000000001,1000000000000001,

%U 1000000000000000000000000000000001,1000000000000000000000000000000000000001

%N Smallest number of the form 10^k +1 with n distinct prime divisors.

%e a(5) = 1000000001= 7*11*13*19*52579 has five prime divisors.

%t With[{c=10^Range[0,40]+1},Flatten[Table[Select[c,PrimeNu[#]==n&,1],{n,10}]]] (* _Harvey P. Dale_, Aug 12 2012 *)

%Y Cf. A085564.

%K nonn

%O 1,1

%A _Amarnath Murthy_, Aug 31 2003

%E More terms from _Sascha Kurz_, Sep 22 2003