%I #14 Dec 24 2022 04:55:01
%S 17,262657,1267650638007162390353805312001,
%T 31828687130226401637050536789795514059715404495050094614691019248562308626412218127220737
%N a(n) = (2^p^3 - 1)/(2^p^2 - 1) where p = n-th prime.
%t Table[(2^Prime[n]^3 - 1)/(2^Prime[n]^2 - 1),{n,4}] (* _Stefano Spezia_, Dec 23 2022 *)
%Y Cf. A051154, A051155, A051156.
%K nonn,easy
%O 1,1
%A _N. J. A. Sloane_