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%I #41 Apr 22 2024 13:16:13
%S 4,6,38,454,510
%N Numbers k such that the k-th Euler number (A122045(k)) is prime.
%C Equals 2*A014547.
%C No others for k <= 69574 (Simon Plouffe). - _Eric W. Weisstein_, Aug 24 2020
%C No others for k <= 112130 (Simon Plouffe). - _Eric W. Weisstein_, Apr 15 2024
%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/EulerNumberPrime.html">Euler Number Prime</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/IntegerSequencePrimes.html">Integer Sequence Primes</a>
%t Position[EulerE[Range[600]], _?PrimeQ] // Flatten
%t Select[Range[600], PrimeQ @* EulerE] (* _Eric W. Weisstein_, Apr 12 2024 *)
%Y Cf. A000364, A014547, A122045 (EulerE), A092823.
%K nonn,hard,more
%O 1,1
%A _Eric W. Weisstein_, Jan 26 2005