A139298 - OEIS

%I #10 Aug 28 2017 03:13:55

%S 8,2048,576460752303423488,

%T 3618502788666131106986593281521497120414687020801267626233049500247285301248

%N a(n) = 2^(2p - 1)/4, where p is the n-th Mersenne prime A000668(n).

%F a(n) = 2^(2*A000668(n) - 1)/4 = A139294(n)/4.

%K nonn

%O 1,1

%A _Omar E. Pol_, Apr 13 2008