A098147 - OEIS

%I #5 Jul 07 2023 21:03:27

%S 5,11,3,1,1,1,1,1,13,3,7,7,15,13,3,3,15,7,1,19,3,19,13,29,7,7,3,27,13,

%T 3,1,9,9,9,27,7,3,7,49,55,81,3,3,9,7,11,69,7,19,13,39,7,1,3,13,13,39,

%U 77,27,63,31,51,19,9,27,3,1,39,19,41,21,67,37,63,69,33,3,9,37,67,121,9,21

%N Difference between first odd semiprime > 10^n and 10^n.

%H Dario Alpern, <a href="https://www.alpertron.com.ar/ECM.HTM">Factorization using the Elliptic Curve Method.</a>

%F a(n)=A098146(n)-10^n.

%e a(2)=11: The first odd semiprime following 10^2 is 111=3*37; 111-100=11.

%Y Cf. A098146, A033873 difference between first prime > 10^n and 10^n.

%K nonn

%O 1,1

%A _Hugo Pfoertner_, Aug 28 2004