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%I #4 Mar 30 2012 17:30:55
%S 5,17,1889,21377,183809,83969,40961,79003649,245235713,5767169,
%T 1004535809,897581057,41238396929,13555990529,2357400174593,
%U 3438121320449,12360915877889,188188287041537,286010462175233
%N Smallest prime p such that both (p-1)/2^(2n-1) and 2^(2n-1)*p+1 are primes.
%C I have found no primes less than the 10^7th prime where an even power of 2 results in the two prime forms above simultaneously except for 2^2 and p=13.
%t f[n_] := Block[{k = 1}, While[ !PrimeQ[k] || !PrimeQ[(k - 1)/2^n] || !PrimeQ[2^n*k + 1], k += 2^n]; k]; Table[ f[n], {n, 1, 37, 2}]
%Y Cf. A059455, A085958, A086476, A086477, A086478.
%K nonn
%O 1,1
%A _Robert G. Wilson v_, Jul 26 2003
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