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”).

Numbers k such that the number of distinct prime factors of 2^k - 1 is greater than the corresponding count for 2^k + 1.
3

%I #6 Sep 25 2020 00:00:48

%S 4,8,10,12,16,20,22,24,28,30,32,36,39,40,43,44,45,48,50,52,55,56,58,

%T 60,63,64,66,68,70,72,75,76,79,80,84,87,88,90,92,94,96,99,100,102,104,

%U 106,108,110,112,116,117,119,120,124,126,128,132,135,136,140,144

%N Numbers k such that the number of distinct prime factors of 2^k - 1 is greater than the corresponding count for 2^k + 1.

%o (PARI) for(n=1,150,if(omega(2^n-1)>omega(2^n+1),print1(n,", ")))

%Y Cf. A046799, A046800, A067886, A337810, A337811, A337812.

%K nonn

%O 1,1

%A _Hugo Pfoertner_, Sep 23 2020