%I #4 Jan 04 2020 16:29:42
%S 2,4,6,8,30,32,126,128,8190,8192,131070,131072,524286,524288,
%T 2147483646,2147483648,2305843009213693950,2305843009213693952,
%U 618970019642690137449562110,618970019642690137449562112
%N Nearest-neighbors of Mersenne primes.
%t {#-2,#}&/@(2^MersennePrimeExponent[Range[10]])//Flatten (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jan 04 2020 *)
%Y Cf. A000668.
%K easy,nonn
%O 1,1
%A _Omar E. Pol_, Nov 27 2007