%I #16 Mar 14 2022 16:11:50
%S 4,6,4,8,6,5,5
%N Number of Mersenne prime exponents between 10^n and 10^(n+1).
%H GIMPS, <a href="http://www.mersenne.org/">Great Internet Mersenne Prime Search</a>
%e There are 4 Mersenne prime exponents between 10^0 and 10^1; 6 between 10^1 and 10^2; ... . There are 9 known Mersenne primes between 10^7 and 10^8 so for now, the next entry is 9.
%Y Cf. A000043.
%K nonn,hard
%O 0,1
%A _Marvin Ray Burns_, Jun 18 2000; updated Jan 07 2006, Jan 15 2009