%I
%S 1,3,171,97641,143239347,626958621819
%N The smallest integer k  2^k + 1 such that omega(k) = n.
%C Conjecture: a(n)  a(n+1).
%C If the conjecture is right, then a(6) = 5519116747872657, a(7) = 50428169725312467009, a(8) = 2073253341916771456141017, a(9) = 163345411049596672714982306379, a(10) = 14245516643046375424146321921618969.
%o (PARI) v = readvec("v006521.txt");
%o a(n) = {k=1; while(omega(v[k]) != n, k++); v[k]; };
%o (PARI) a(n) = my(m=1); while((Mod(2, m)^m!=1)  (omega(m)!=n), m++); m; \\ _Michel Marcus_, Feb 16 2019
%Y Cf. A006521, A001221 (omega).
%K nonn,more
%O 0,2
%A _Jinyuan Wang_, Feb 15 2019
