%I #25 Aug 24 2020 22:44:08
%S 2,3,19,227,255
%N n-th Euler (secant, zig) number A000364(n) is prime.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/EulerNumber.html">Euler Number.</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/IntegerSequencePrimes.html">Integer Sequence Primes</a>
%t Select[Range[100], PrimeQ[EulerE[#]] &]/2 (* _Harvey P. Dale_, Aug 10 2011 *)
%Y Cf. A000364.
%K more,nonn
%O 1,1
%A _Eric W. Weisstein_
%E Offset corrected by _Arkadiusz Wesolowski_, Oct 17 2011